Find frictional force from mass and acceleration

In summary, frictional force is the force that resists the motion of an object due to contact with its surrounding surface. It is directly proportional to the mass and acceleration of the object. The formula for calculating frictional force is F = μN, and the coefficient of friction can be determined experimentally. Frictional force is not always constant, but for practical purposes, it is assumed to be.
  • #1
liz777
19
0

Homework Statement



Acceleration of a car is -12.2 m/s/s. The car has a mass of 925 kg. Find the frictional force.


The Attempt at a Solution



So A=-12.2, M=925 kg

Fnet=MA
=925(-12.2)
= -11285 N

Fg=mg
=925(9.8)
=9065 N

Since there is no vertical direction, Fg=Fnorm.

Now I have the equation Ff(frictional force= coefficient(normal force)

I'm really stuck here. I need to know the Fa or the coefficient to solve?
 
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  • #2
If that's the whole questions then Fnet=Ff=ma

so you got it..
 
  • #3


I would first clarify the context of this problem. Is the car in motion or at rest? Is the acceleration due to an external force or is it caused by the frictional force itself? These details are important in determining the appropriate equation to use to solve for the frictional force.

If the car is in motion and the acceleration is due to an external force, then the frictional force can be found by subtracting the net force (Fnet) from the force of gravity (Fg). This would give us the following equation:

Ff = Fg - Fnet

Ff = (925 kg)(9.8 m/s^2) - (925 kg)(-12.2 m/s^2)

Ff = 9065 N + 11285 N

Ff = 20350 N

If the car is at rest and the acceleration is caused by the frictional force, then we can use the equation Ff = μFnorm, where μ is the coefficient of friction and Fnorm is the normal force. However, without knowing the coefficient of friction or the normal force, we cannot solve for the frictional force in this case.

Therefore, in order to fully solve this problem, we need more information about the context and the forces acting on the car. I would suggest reviewing the given information and clarifying any missing details before proceeding with the solution.
 

FAQ: Find frictional force from mass and acceleration

1. What is frictional force?

Frictional force is the force that opposes the motion of an object due to the contact between the object and its surrounding surface.

2. How is frictional force related to mass and acceleration?

The frictional force is directly proportional to the mass of the object and the acceleration of the object. This means that as either the mass or acceleration increases, the frictional force also increases.

3. What is the formula for calculating frictional force?

The formula for calculating frictional force is F = μN, where F is the frictional force, μ is the coefficient of friction, and N is the normal force between the object and the surface.

4. How do you find the coefficient of friction for an object?

The coefficient of friction can be found experimentally by measuring the force required to move an object with a known mass over a surface, and then using the formula μ = F/N.

5. Is frictional force always constant?

No, frictional force can vary depending on the surface, the object, and other factors such as temperature and surface conditions. However, for most practical purposes, it is assumed to be constant.

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