World on Fire: Tips, WIKI Reviews

WORLD ON FIRE is a strategic Android game with a release date of December 6, 2018 from the company WoF Games. After a global catastrophe, you will rebuild your military base and lead it to victory. In this article we will describe how to properly develop the base, build troops and win even in losing situations. Attention, the article is periodically updated, look at the site Wise Geek more often.

Table of Contents

  1. Exchange Code (Gift)
  2. Overview Guide for Newbies
  3. Resource Guide
  4. Player Base and Defense
  5. Army Guide
  6. Talent Guide
  7. World Map
  8. Guide to the Corps (guild)
  9. The Wise Geeks Secrets and Tips

World on Fire: Exchange Code (Gift)

Where to get the exchange code? The game provides incentives for active participants of the official Facebook page https://www.facebook.com/WorldOnFireGame/ . Here, often the administration holds draws, the results of which are issued exchange codes. Each winner is given an individual promotional code in the message.To participate, you must be subscribed to the page, as well as put screenshots of your base under each post with a drawing.

Where to enter the exchange code? To enter the code, click on the avatar of the character in the upper left corner of the screen. Then click on the "Gift exchange" button. To receive more exchange codes, it is recommended to subscribe to the "WoF" page. The exchange code can only be used once.

World on Fire: Overview Guide for Newbies

World on Fire is a military strategy from the company CAMEL GAMES. The game takes place in the future.After numerous wars for power, the planet suffered destruction. Even more, the Earth was hit by a meteorite strike. But people did not stop it. Many desperate brave men rebuilt the remnants of military bases and fought for power and survival. Only a wise tactician will be able to seize the Floating Fortress and become the ruler of the state.

Getting into the game, the gamer will find the remains of the base, a few patches of land for farming, several buildings. Now this is the main place of action of the player. The commander will be met by an assistant who will share his experience with the commander.

The main task of the player is to rebuild the base for defense, recruiting units, to increase the power. There are a lot of buildings in the game, each of which brings additional power to the commander, performs certain functions. Buildings need to be improved to strengthen the base and improve the characteristics of the building.

The hull is also an important part of the gameplay. Very many missions and conquests take place in the guild.You should try to join the guild as quickly as possible. This will affect the speed of base development. Since the corps members can not only accelerate construction, but also develop technologies that also affect many aspects of the construction and operation of the players base.

VIP points are required to get bonus player privileges (speeding up construction, increasing the basic characteristics of the army and character). In World on Fire VIP points can be obtained for completing tasks and when a player moves to a new level. VIP points are also given to the player for daily entry into the game. The more consecutive entries, the more VIP points you can get. But, each VIP level requires activation. Moreover, the activation is given for a certain amount of time. If the player does not use a paid subscription, then for playing time you can use bonus VIP cards that activate the privileges for 1, 2, 3 and 6 hours. These cards are given for certain tasks.

World map - you can get out of the base at a certain level. On the world map there are other bases of players that can be attacked. There are also resource extraction sites. There are rebels who often organize rebellions. It should make raids on the camps of the rebels.

Battle. The task of each commander to collect as many different troops as possible. Battles with players take place in real time, before the battle, you can arrange the troops. Attacking the rebels or sending troops to extract resources, you can build several units.

Sending one or several detachments in the march, you must leave part of the army at the base to protect it. Thus, a tactician can simultaneously perform several strategic tasks.

World on Fire: Resource Guide

The game has 3 types of core resources:

Provisions - needed for the construction of buildings, hiring units. You can get for the performance of tasks on the farm when collecting, get on the World map in special places (farms). Resource can be obtained after a successful attack on the rebels, or after a campaign in the ruins. The army does not use provisions, so it can be easily accumulated.

Iron - it is necessary for the construction of buildings, the hiring of equipment, the construction of super-weapons, the repair of Fur (fortification). You can get for the performance of tasks, to be made in the Steelworks, mined on the World map in special places (steel mills, factories). Resource can be obtained after a successful attack on the rebels, or after a campaign in the ruins.

Gold is the rarest resource. It is necessary for the purchase of valuable things, for the immediate construction of buildings, for the acceleration of construction, for the improvement of weapons and the acceleration of their production, for the immediate hiring of troops. For gold, you can accelerate the process of studying science in the Technical Center. The resource can be donated to the guild (Corps). Gold is exchanged for dollars from Merchant resources on the Battleship and other resources are purchased. In short, gold is an important and necessary resource.

Gold is given for completing special missions, for a new character level. The resource can be received the first 7 days for the daily entry into the game and with participation in the events. Rarely and in small quantities, gold falls from raids on insurgents and debris. Also, gold can be bought for real money.

It is important to remember that at the start of the game for the promotion of a beginner, several sets (from 20 units) will be issued for the easiest tasks, so you need to save it and not spend on speeding up buildings or recruiting units. Over time, the resource may be needed to purchase rare ingredients for a super-weapon or character ammunition. If the player is not going to invest real money in the game, then the savings should be taken care of in the first stages of the game.

Other resources are mainly materials for the manufacture of weapons and equipment. There is oil that is processed into engine oil and gasoline. These resources can be purchased from the Resource Merchant and in the Corps shop, produced at Remzavod. The player will receive some rare materials after charging a super-weapon, when attacking the rebels, going to the ruins.

World on Fire: Player Base and Defense

Base Overview

In the first moments of the game, you should familiarize yourself with the main buildings, what they are for and what functions they perform.

Barracks - this is the first building that the game will offer to build a novice. Follow the prompts to properly place the building. In the game, each building has its place. In the barracks, the player will recruit troops. At the start there are only a few types of vehicles and infantry, but over time, new cars will open that will bring victory to the gamer.

Farm - will help to get and store provisions. By increasing the level of construction, you can increase the production speed and storage volume. Reaching a warehouse limit, production stops. Therefore, it is important to collect resources on time.

Hospital - allows you to treat wounded soldiers. The higher the building level, the faster the healing takes place and more units can be cured at the same time. For successfully completed tasks, the commander will be given bonuses to speed up the treatment of wounded soldiers. You should not spend them just like that, it is better to leave bonuses in case of an attack on the base, when you can immediately heal the troops.

A steel mill is a place where iron is produced and stored. Improving the construction, the player increases the storage capacity and speed of production of the resource. To start recycling, click on the building and select the "Production" menu.

Platz - serves as a strong point for recruitment. By improving the structure, you can increase the capacity of units.

Event - in this building you can see what events are happening in the game at the moment, and the amount of time until their completion. Take part in the event and learn more about it by clicking on the arrow with the name of the event. For some events there are limitations. For example, you need a certain level or amount of character power. For the first 7 days of the game you can get a reward here.

City Hall - this building does not need to be improved. It bought for real money subscriptions, upgrade kits and many other things. In the "Daily Reward" you can get bonuses for certain achievements in the game. As soon as the scale under the achievement reaches a maximum, the commander receives a bonus.

Warehouse - protects resources on the base during an attack. By improving the warehouse, you can increase the limit of its resources. In a separate menu, you can allocate resources.

Radar - allows you to get information about the marching troops of the enemy. The higher the radar level, the more accurate the data received. Over time, the player will receive complete information about the attacking enemy (number of troops, types of armies, power, time before the attack).

Battleship - the first 7 days the player receives bonuses for daily entry into the game. The bonus can be seen by clicking on the "Daily Reward" button. The "wealth center" provides an opportunity (as in the mayors office) to get tasty bonuses for real money. The resource trader sells for dollars (gold can be immediately exchanged for money) resources. The merchant will become available from Headquarters level 10.

The military enlistment office - improving the building, the commander increases the number of recruited troops (not to be confused with the number of units in the units). That is, a player in the same period of time will receive a greater number of soldiers.

Embassy - here is the data of reinforcement troops, which are located on the players base or outside its perimeter. Raising the level of the building increases the number of support troops.

Fort - raises the base defense limit. Over time, when the armistice shield falls from the base, other commanders will attack the player. To always have the opportunity to confront the enemy, it is necessary, as far as possible, to improve the Fort. It is directly connected with the Headquarters (improvement of one building is impossible without raising the level of another building).

Headquarters

The headquarters is the main building, which determines the level of the base as a whole. If you click on it, you can see several control menus:

  1. Buff - here you can purchase various bonuses for the base and the army (shield, acceleration, attack increase). All bonuses are bought for gold.
  2. Database data - here is located information about the database (economy, power indicators, level of development).
  3. Improve - by clicking on the button, you can improve the building (raise the level). You can also see the time for which the structure will improve. If the "Improve" button is not active, here is shown what other conditions need to be fulfilled before raising the level (there is such a menu on each building).
  4. Details - shows the current characteristics of the Headquarters, what effects it gives at the current level.

Technical Center

This is a kind of academy where you can explore the sciences that affect the level of development of the base, the power of the character, the speed of collecting resources. To explore the technology of a higher class, you need to raise the level of the structure. The game has 4 types of sciences:

  1. Military technologies - new skills are concentrated here that affect the attack, defense, health and speed of troops, the number of units increases, their payload improves (an important criterion when collecting resources).
  2. Resource technologies - include the science of mining and production of resources.
  3. Technology development - here are studied: treatment, trips, construction and many other necessary skills.
  4. Defense technology - science to protect the base.

Each studied technology increases the power of the character, base and army.

Armory

Here is the ammunition for the character. Each piece of equipment has its own parameters that affect the power of the army. You can create several sets of ammunition, each of which will be necessary for a particular event.

For example, if a player performs a campaign against another commander (or appears in the Corps army), then it is necessary to change the character into equipment that increases the armor and attack of the army. If a player sends troops to the extraction of resources, it is better to change into clothes, which increases the speed of movement and the capacity of the troops. This will help to quickly collect the cell and carry more resources.

To create ammunition need to collect materials. They can be found on the World Map, to get in the attack on the rebels or destroyed ships. Also materials can be obtained by successfully completing tasks. In the Corps shop often lay out some rare ingredients. Resources can be bought for real money in the City Hall or on the Battleship from a merchant.

At the start of the game you should not collect everything. In the first stages of the game, it is necessary to manufacture ammunition for defense and attack by the army. Over time, you can collect other items. From the first moments of the game, it is important to properly allocate resources, the combat capability of the troops will depend on it.

Creation of ammunition. The higher the level of weapons, the better the equipment created. For gold, you can speed up the manufacturing process. The higher the class of materials used, the easier it is to create high-grade ammunition. By improving the Armory, you can unlock things of a higher class and reduce their production time.

Removod - opens at the 10th level of the Armory. The building can produce the necessary materials to create ammunition, the functioning of technology (oil, gasoline). Improve the building is not necessary.

Base protection

In World on Fire base protection depends on the strength of the character and the number of units in the army commander. A certain percentage of fighters and equipment is reserved to protect the base. This is an important moment in the game, because they will attack the camp daily. With defense you can lose not only units, but also the main resources of the commander. During the siege, the base begins to burn, while the strength of the walls gradually decreases. As soon as the scale of strength drops to 0, the base is automatically transferred to any place on the World Map (often a player may be on the very edge of the map, where resources are collected very slowly and there are few of them).

Mechanical installation (Mechs). At the first stages of the game it is recommended to repair the Furs, which is located on the walls of the base. The mechanism will significantly increase the power of the character and the protection of the base. In the Furs menu you can change the setting. Each fur has its own function. To change the Fur, click on its avatar (after repair). During the battle, the expedition to the ruins, attacks on other bases consumed the energy of the Fur, while he is given the experience. Energy is restored automatically, but slowly (you can accelerate with gold). With each new level, the characteristics of the installation and energy increase, the speed of energy recovery increases. The level of the robot can not exceed the level of Headquarters.

After upgrading, you can upgrade Furs and gain new skills or skill panels.

The robot has 2 types of skills:

  1. Active - if necessary, the player can activate them. Active skills do not change.
  2. Passive - work constantly and do not depend on the desire of the commander. Passive abilities can be changed and used on different mechanisms.
Robots can participate in the defense of the base, in attacks on other camps, but they cannot participate in resource squads and extract resources.

All troops, while in the camp, participate in the defense during the attack. In the early stages of the game, the collection of resources on the World Map is very fast, thanks to the low payload of the troops. But in the later stages of the game, the gathering may take several hours. Therefore, it is recommended to divide the army into several units. In the defense should leave tanks and artillery, which will attack opponents from a distance. If the superweapon does not participate in the march, then it will also defend the camp. Independently build troops on the walls is not possible. But, thanks to the separation of units, the game will automatically build at defense.

The defense can be enhanced by the characters ammunition: before leaving the game, you can change the heros gear into equipment, which increases armor and defense of troops. This will enhance the combat capability and allow longer to defend, perhaps, to win (usually players with a high level attack). If the novice takes a lot of trouble to the attacking player (in the form of the dead), then the next time the commander will bypass the problem base.

World on Fire: Army Guide

You can recruit troops in the barracks. To do this, click on the Barracks and select the menu "Recruit". A menu for selecting units will open. Here are all types of troops. At the start 100 tanks are available. With the increase in the level of the Headquarters, new types of equipment and infantry will be opened.

Main characteristics (in the hiring menu, the player can see the characteristics of the type of army being purchased):

  1. Fighting capacity.
  2. The number of lives.
  3. Attack.
  4. Protection.
  5. Attack radius.
  6. Movement speed.
  7. Tonnage (payload).

For these characteristics, you can compare the troops among themselves. Over time, all types of army will open and more powerful units will appear. It is impossible to improve the purchased troops, but new types of troops will correspond to the level of the character.

Each kind of military has its own passive skills. It is recommended to rationally combine them to increase the maximum power of the army.

The game has 4 types of troops:

  1. Tanks - have high attack and defense power, but have very low movement speed. In the battle, it is recommended to put them on the first line to cover the rest of the troops.
  2. BMP (armored infantry vehicle) - has good attack and defense power, has a high speed of movement. Machines are recommended to be installed from the flanks, they are maneuverable and the attack can be started from any unexpected angle.
  3. Infantry - has the average performance. With the support of tanks and infantry fighting vehicles capable of inflicting high losses on the enemy. Infantry in the battle should be put in the center for the tanks.
  4. Artillery - has low rates of protection and life, but have a high destructive power, they hit long distances. Artillery is better placed on the most distant line in the battle, so that the enemy could not reach it.
If you choose the right units to collect resources (for example, take a BMP) to attack other bases (combine all types of troops), leave tanks and artillery at the base as a defense, you can successfully defend and attack simultaneously.

The characteristics of the army are influenced by the technologies being studied in the Technology Center (the War tab), as well as the characters ammunition. Parameters can be enhanced if you develop the talents of the hero and super-weapon.

Energo - Academy

Super weapons can be assembled and activated in the Energy Academy, which opens at level 10 of the Headquarters. By improving the Academy, you can open more slots to activate different types of weapons. The Academy has 3 menus:

  1. Super weapon charge - chests with valuable resources and bonuses are given for each charge. Sometimes you can get a super weapon. You can load a weapon as many times as you like, as long as you have enough resources for it. There is a shop in the menu where you can buy charges.
  2. Super weapon - a super weapon is assembled in this menu. Weapons are assembled from fragments, which can be obtained in events, from gifts and with the help of charging.
  3. Energy - matrix - here the player can place a weapon. As soon as the superweapon is placed in the slot, the base power will increase, plus the army will receive additional reinforcement characteristics.

Super weapon. Fragments can be exchanged for materials for super-weapons. Each weapon adds a good bonus to the parameters of all types of troops. Weapon class is determined by color:

  1. Blue - the usual super-weapon, with mediocre characteristics.
  2. Violet - has good performance, significantly increases the power of the base and the army.
  3. Orange - the most powerful super-weapon, has elevated performance.

You can only get 1 weapon of each type. A similar weapon will be broken into fragments. Strengthening a weapon increases its strength. Power is expended on gain. Each modification allows you to increase the stardom of the weapon and unlock the star attributes. Fragments are needed for modernization. Each upgrade affects the level of super-weapons.

Competently combining all the military parameters, the player can significantly strengthen the army.If you simultaneously develop other abilities of the base and character, you can achieve high power without making real money in the game.

World on Fire: Talent Guide

In the game, WoF is all interconnected. Before you go to the description of the talents of the character, you should consider the menu "Tasks". Here you can see the current outstanding tasks. Assignments are distributed by type.For each completed task you can get valuable bonuses and resources. It is advised to first perform the recommended tasks in order to get more bonuses. Performing tasks for the construction and improvement of buildings, the player receives skill points that can be distributed in the menu "Character data."

Technology character. In order to get talents, it is necessary in the "Character Data" to go to the tab "Character Technologies". There are 2 branches of talent development:

  1. War - here army performance improves: attack, defense, recruitment acceleration, improvement of parameters by type of troops, equipment durability increases. There is an active skill (activated by the player) "Withdrawal of troops". By clicking on it, you can instantly return the troops home.
  2. Development - the base parameters are improved here: acceleration of construction, increase in tonnage of units, increase in production, production speed.

Skills "Development" should be improved first of all from the start of the game. Each talent carries not only direct meaning, but also hidden implication.

Increasing the speed of construction - allows you to quickly rebuild and raise the level of buildings. The faster the base will be rebuilt, the faster the player will receive maximum bonuses from buildings, increase power, will be able to produce more resources.

Increasing the capacity of the army - since at the high levels the main source of resources will be collection on the World Map, it is important to take a large amount of materials at a time because other players can attack the caravan, kill units (and this is extra time for their recovery). At high levels there is no need to hire troops specifically to transport cargo, you can improve your talent and use the weaker troops hired at the start of the game.

Increased production - at high levels, many provisions and steel are needed to improve buildings, and a lot of resources are required to increase the level of Fur. This talent will allow gathering more resources in the same period of time, thereby accelerating the development and protection of the base.

Harvesting is an active skill that, when activated, gives 6-hour production for 4 types of resource buildings, thereby increasing the speed of collection.

Research takes place in order, if maximally improve 1 talent, the following skill will not open for study. These Skills Technologies differ from studies at the Technology Center. There you can just 1 time to learn all the skills in turn, and then maximize the most necessary.

It is recommended to study the skills of the character synchronized with the research in the center.This will give a double bonus to the characteristics of the base at the same time.

World on Fire: World Map

In the lower left corner of the main screen is a button with a picture of the landscape, it allows the player to go beyond the base. On the map, you can extract the main resources, you can attack the bases of other players. By activating the "help a friend" function, the unit will automatically be sent to the aid as soon as the ally is besieged.

The world map is divided into zones - resource cells. The closer to the center of the map, the more resources can be collected from one field (farm, plant). In the center of the harvest rate is higher than in the periphery. This aspect makes it possible to collect resources more and faster.

By placing the base in the center of the map, you can accumulate a sufficient amount of resources in a short period and rebuild the base faster. But it should be remembered that many other players will also strive to locate the base in the center of the map, so you need to take care of protection (for example, purchase a shield) and the speed of collecting resources.

In the very center of the map is the Floating Fortress - a symbol of power in one state (on the game planet, the number of states is equal to the number of existing servers). Only a strong Corps can capture it. In the battle for the Floating Fortress is determined by its owner. Competitions are held in 2 stages:

  1. The battle for the fortress itself, when the guilds fight for the possession of the base.
  2. Protection of the source of energy , when against the Corps - the winner come out to fight several waves of monsters (very strong). If the guild resists a certain time, it will gain power over the state.

The members of the victorious corps will elect a president who will have high authority, can appoint employees and rule the world. The whole Corps will receive rich gifts.

The rebels. On the map there are gaming robots - rebels. The task of the player is to destroy them. At high levels, the rebels will be accompanied by powerful robots. Also on the map there are broken spaceships (ruins) that you can explore. For insurgents and ruins, commanders receive experience and prizes. Sometimes a player can get gold.

The battles with the rebels are automatic. The player will only see his army going to the monsters, a couple of cannon shots and the army returning home. A message about the fight will come to the mail in the "Details" menu. The letter will be a video of the battle. If you wish, you can see it. The ruins can be attacked 2 times a day.Having reached 30 character level, you can take part in the "battle of the brave" 1 time per day.

Search for objects. There are many different farms and plants on the map from which it is necessary to collect resources. To make it easier to find the desired object (including the rebels and the ruins), the developers came up with a search system. Turning from the base to the map, click on the button with a magnifying glass, a search window opens. After selecting an object, you must select its level, for this you need to move the slider to the right, then confirm the action "go."

Base players. By clicking on any database of another player, you can view information about him. The higher the radar level, the more information will be provided. The player can be offered friendship, or send a message. If you want to attack, then you should select the appropriate button.

If an armistice shield is activated on the base, then attacking the opponents, the shield will be canceled and its duration will end.

World on Fire: Guide to the Corps (guild)

The newcomer is recommended to join the guild as early as possible. This will bring some advantages that will increase the power of the base and character.

Body Benefits:

  1. Players receive Corps bonuses (when studying the technology of the corps, the bonus is distributed to all members).
  2. In the Corps shop you can find rare items.
  3. You can jointly attack other corps and individual players.
  4. When attacking the enemy, the allies will automatically come to the rescue.
  5. If during the construction of buildings to send a call for help, the co-guilds will help speed up the construction. The percentage of acceleration depends on the level of development of construction technology in the housing.
  6. Participation in the battles of buildings and joint events.

After entering the Corps, it is necessary to build a Corps Headquarters. After construction, the player receives a defense zone. For the destruction of the rebels in this area, an additional reward is given. The larger the territory, the greater the reward. Other players must pay tax if they extract resources in this zone.



Concentration troops. To attack the rebels with a super weapon, you need to collect concentration troops. A squad must have a maximum of 5 squads (player armies). After exceeding this limit, access will be blocked. When the time of the concentration troops comes out, if there are less than 2 commanders left in the group, the team is disbanded.

Housing technology

Important for all members of the corps, technology affects not only the development of the corps itself, but also the development of the base of each guild member. For each contribution to the technology, the commander receives the "glory of the corps", which can be exchanged in the Corps shop. For each technology there is a specific development time. During this time it is necessary to raise the level of technology. To continue making deposits, you must wait until the control time expires. When the scale of deposits reaches the maximum mark, the technology will receive a new level.

Types of technology:

  1. Production - there are a lot of sciences here that help in the development of the hull and the bases of its members (construction speed, production volume and much more).
  2. War - here are located skills that increase the level of defense of the corps, the protection of the bases of each member, increases the attack of all the armies of the participants.
  3. Others - science affecting the expansion of the body, on taxes, on the time of assistance (this is an important technology, which determines the speed of the arrival of armies when attacking the base of the members of the alliance).

The buildings

Each building chooses a place for the construction of a joint base and headquarters. As soon as the headquarters is built, the boundary of the corpss influence will appear. Within the boundaries of the guild members can put the bases and flags. Flags give the chance to increase borders of the territory of the case. While the Corps has no buildings, the effect of the technology will work at 50%.

Main buildings:

  1. Corps Headquarters - affects production technology. It is built by the leader of the guild.
  2. Fort Corps - affects military technology. Protects players in the alliance.
  3. Flag - affects the population (the number of members of the alliance) and other technologies.
Each member of the Corps is obliged to contribute to its development, only together you can make the alliance strong, which will win the competition, and in the future, it may become the ruler of the state.

The Wise Geeks Secrets and Tips



How to increase the power of the player? In order to increase the power of the base (player), you should regularly perform a number of actions:

  1. Daily enter the game and perform tasks. For this give the experience of the character that affects the power of the base.
  2. To raise the level of buildings, build new buildings (barracks, farms, steel mills, hospitals).
  3. Perform recommended tasks, participate in events.
  4. You should join the hull and improve hull technology.
  5. It is necessary to increase the talents of the character, explore technology in Technocenter.
  6. To produce high quality ammunition.
  7. Activate VIP level.
  8. To conduct raids on the rebels and in the ruins.
  9. Improve Furs and super weapons.

Why is the term "character" introduced in the game when there are no heroes in the game? Yes, this term was introduced due to the fact that a player on 1 server (in the state) can have two bases. But to create a second base, you need to start building power from scratch.Yes, and lose the already rebuilt property, few people want. Therefore, the developers have given the opportunity to keep a remote first base, but on the condition that the game will be tied to an account on Facebook or Google. In fact, the old base occupies a certain cell on the map, but the players do not see it. If there is a need to return to the first base, you just need to change the character in the settings (the name of the base). And technically, during the game you should equip the player, but visually it should somehow be displayed.

How to speed up energy recovery? The energy in the game is generated only from the Mechs. If it is consumed, it is restored for a very long time. To accelerate, it is necessary to raise the level of Fur, as well as to maximally explore the relevant science in the Technocentre. In the Headquarters for gold, you can purchase a bonus to the restoration of energy (expensive).

How to change the color of ammunition? No, you need to create a new outfit. If you need to improve equipment, this can be done with the help of special materials.

Why cant I start construction if all conditions are met? Make sure that another building is under construction (or is improving). If the construction is currently underway, you should wait for its completion. But you can hire a detachment of builders (bonus), which will produce construction parallel to the main construction (acceleration).