# Homework Help: Identifying all the forces

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1. Nov 9, 2014

### Soniteflash

1. The problem statement, all variables and given/known data
A
crate sits in the back of a truck that is accelerating to the right. The crate does not move relative to the bed of the truck. Draw the free body diagram and sum the forces for the crate only.

2. Relevant equations
F⃗ net=ΣF⃗ =ma⃗

fs≤μsN

3. The attempt at a solution

S
o the problem says that the crate does not move relative to the truck. With that in mind, the reason why the crate is not moving is because the static friction is to great for it to be overcome by a force. I am kinda confused about which forces are acting on the crate. I know that there is the normal force, weight and static friction.
Attempt: ΣF⃗x =Fa-Fs=ma=0

ΣF⃗y=Fn-Fmg=MA=0

So if there was no friction involved, would that mean that the crate would move to the left relative to the bed of the truck?

2. Nov 9, 2014

### phinds

Right. (or in this case, it might be less confusing to restate that as "correct";))