# Why does a car apply a force to a wall?

• Selfphysicslearner
In summary: Without saying anything more, it seems that you are not entirely sure what the situation is. In summary, the car does not hit the wall and come to a standstill, but the force that acts on the car is -32 000 Newtons.
Selfphysicslearner
when we have 0 acceleration(constant speed) like a car traveling at a constant speed,
ƒnet=ma
ƒnet=(mobject+mfriction).(aobject+afriction)
let m object be 1500 kg.
m friction be 10 kg
a object be 0
a friction be 20m/s^2
so when we calculate fnet=-20*1600=-32 000 Newtons.
which means wall applies force towards car but the situation isn't like this.
questions:where did I make a mistake?
2-does friction have a mass or acceleration?

Selfphysicslearner said:
when we have 0 acceleration(constant speed) like a car traveling at a constant speed,
ƒnet=ma
ƒnet=(mobject+mfriction).(aobject+afriction)
let m object be 1500 kg.
m friction be 10 kg
a object be 0
a friction be 20m/s^2
so when we calculate fnet=-20*1600=-32 000 Newtons.
which means wall applies force towards car but the situation isn't like this.
questions:where did I make a mistake?
2-does friction have a mass or acceleration?
This is not good. I guess from your name you are self-learning physics. There are some fundamental problems here. An object has only one mass. The idea of a friction mass is not valid. I can't imagine where you got that idea from.

Selfphysicslearner said:
friction have a mass or acceleration?
No. None of the two. Friction is a force.
Dimension mass times length divided by (time squared)
Units kgm/s2

So that is the mistake you make.

In your ##f_{\rm net} = m\, a##
##m## is the mass of the object​
##a## is the acceleration of the object​
##f_ {\rm net} ## is the net force on the object : the vector sum of one or more of the following:​
• gravity
• normal force
• friction
• external force(s)

PeroK
Selfphysicslearner said:
where did I make a mistake
There is problem in that you have not actually stated the situation / problem - except implied in the title.
It's sometimes very hard to get started with this sort of thing and you need to marshal your thoughts if you want to make progress with it.
Does the car hit the wall and come to a standstill?
Do you want to know the Force that acts on the car?
Where do you think friction comes into the collision calculations?
What do you know about collisions and the rules that we apply in calculations about collisions?
A diagram could help, perhaps - either draw one just for yourself or post it.

Selfphysicslearner said:
...but the situation isn't like this
What is the situation like then?

PeroK said:
I guess from your name you are self-learning physics.
Or learning self-physics.

sophiecentaur

## 1. Why does a car apply a force to a wall?

A car applies a force to a wall because of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. When a car collides with a wall, the car exerts a force on the wall, and the wall exerts an equal and opposite force back on the car.

## 2. What factors determine the amount of force a car applies to a wall?

The amount of force a car applies to a wall depends on several factors, including the speed and mass of the car, the angle and surface area of contact between the car and the wall, and the materials and structural integrity of both the car and the wall.

## 3. Can a car's force on a wall be negative?

No, a car's force on a wall cannot be negative. According to Newton's third law, the forces between two objects are always equal and opposite, so the car's force on the wall will always be in the same direction as the wall's force on the car.

## 4. How does the force of a car on a wall affect the car's motion?

The force of a car on a wall can significantly affect the car's motion, depending on the magnitude and direction of the force. If the force is large enough, it can cause the car to come to a complete stop or change its direction of motion. In some cases, the force can also cause damage to the car and the wall.

## 5. Is the force of a car on a wall the only factor that determines the damage caused?

No, the force of a car on a wall is not the only factor that determines the damage caused. Other factors, such as the speed and angle of impact, the design and materials of the car and the wall, and the presence of safety features, can also impact the amount of damage caused by a car colliding with a wall.

• Mechanics
Replies
2
Views
2K
• Mechanics
Replies
5
Views
1K
• Mechanics
Replies
4
Views
1K
• Mechanics
Replies
15
Views
2K
• Mechanics
Replies
5
Views
1K
• Mechanics
Replies
20
Views
7K
• Mechanics
Replies
16
Views
1K
• Mechanics
Replies
6
Views
996
• Mechanics
Replies
6
Views
3K
• Mechanics
Replies
8
Views
3K