How Far Did the Robber's Car Travel in 6 Seconds with a Forgotten Brick of Gold?

[jk2455]

Homework Statement

During a bank robbery, one of the gangsters forgets a brick of gold on the roof of the
car. Assuming that the car accelerates from rest with a constant acceleration, and that the
brick was on the point of slipping, throughout the acceleration, how far did the car travel
in the first 6s if µs = 0.4?

(the answer is 70.56m)

The Attempt at a Solution

1. Homework Statement [/

givens:
x direction---> a=? delta x=? initial velocity=0 final velocity=?
y direction---> a=0 delta y=0 " " " = 0
mu=o.4 t=6

Homework Equations

x=(initial velocity)( time )+ 1/2 (a)(t)

The Attempt at a Solution

Homework Statement

Homework Equations

The Attempt at a Solution

 

[The legend]

you have to attempt a solution first.

 

[jk2455]

but i am not sure where to start could someone give me a hint

 

[The legend]

I am assuming the friction to be only between the car and the block.
say the frictional force is f=µs*m*g. but this has to be equal to the force acting on it.
so equate it to m*a and get a value for the acceleration.

Use the equations of motion where you know a, u, and t...and hence find s.

 

[jk2455]

thanks :)

 

[The legend]

you'r welcome!