force with a car and wall.?

Question

An 1800 kg car traveling at 5 m/s strikes a wall. If the car comes to rest in 0.5 sec then the average force of the wall on the car is??

little confused on how to do this, please help, thanks

sorry supposed to be traveling at 35 m/s strikes a wall

Answer 1

Δvelocity = acceleration * Δtime

The car changes its velocity from 35 m/s to 0 m/s, which amounts to a total change of 35 m/s.
Δv = 35 m/s.

The car’s velocity changes in the time span of .5 seconds we are told in the problem.
Δt = .5 seconds.

Rearranging the above equations to solve for the average acceleration of the car,
Acceleration = Δvelocity / Δtime
Acceleration = (35 m/s) (.5 seconds)
Acceleration = 70 m/s^2

Now using Newton’s second law,
Force = mass * acceleration

We are told that the car’s mass = 1800 kg

Force = (1800 kg) * (70 m/s^2)
Force = 126000 Newtons

Of course, acceleration and force are vector quantities and I have only listed their magnitudes. It should be obvious the direction of each of the vectors is in the direction away from and perpendicular to the wall which is exerting this force and causing the acceleration.

Answer 2

impulse is change in momentum

J = m * v

F x= = m * v

F* .5 = 1800 * (0 - 35)

F = -126,000N

the negative means the force is opposite of the motion

Answer 3

Impulse = Force x time = change in momentum. The car comes to rest so Ft = -mv;

F = - (mass)(velocity) / (time) = - (1800kg)(35 m/s) / (0.5 s) = -126000 N or -126 kN.