Friction/Dynamic Equilibrium Help

1. Oct 31, 2005

acpyrus

A pickup truck with a steel bed is carrying a steel file cabinet. If the truck's speed is 15 m/s, what is the shortest distance in which it can stop without the file cabinet sliding?

*---*--*-*
v(i)=15m/s
v(f)=0
Need to find x(f)

Friction: f(s) should be F(net) = 0?

Not sure where to start.

2. Oct 31, 2005

dekoi

Are you given a coefficient of friction for the cabinet?
Are you given any other information, such as masses?

I think you need to find the coefficient yourself, for steel on steel.

Last edited by a moderator: Oct 31, 2005
3. Oct 31, 2005

acpyrus

Coeffiecient of friction is not given on the problem, however I did find a steel-on-steel f(s) in a table in our text --> where f(s) = 0.80

4. Oct 31, 2005

dekoi

I am pretty sure the question should be solved as such:

The only force on the cabinet is the static friction.
Due to the cabinet's inertia (since it is already moving forward), the net force is not equal to zero. We want the friction force to move the cabinet in the opposite direction of motion so that it will not slide.

Net force on the cabinet:
Fnet = Fs

ma = μmg
a = μg

Use a kinematics equation to solve for distance, using the calculated acceleration and the known change in velocity.

Last edited by a moderator: Oct 31, 2005
5. Oct 31, 2005

acpyrus

I came up with 14.3m - which is correct. Thanks.