• Support PF! Buy your school textbooks, materials and every day products Here!

What is the magnitude of the frictional force acting on the crate?

  • Thread starter moondawg
  • Start date
  • #1
46
0

Homework Statement



A crate with a total mass of 50 kg is initially at rest on a level floor. A horizontal force of 150N pushes the crate across the floor at a constant acceleration of 1.2m/s2. What is the magnitude of the frictional force acting on the crate?

Homework Equations





The Attempt at a Solution


So this question seems so basic but I know I'm doing it wrong. All i did was plugged the numbers into the F=[tex]\mu[/tex]N formulas and got [tex]\mu[/tex]= .31. But in using that formula I am not even taking into account the acceleration and I dont know what to use in order to take it into account?! Someone please explain
 

Answers and Replies

  • #2
648
2
It's just F=ma on the crate, but remembering that there are 2 forces acting here; the 150N and the friction.
 
  • #3
forces.gif
 
  • #4
forces.gif
It means that if 50N force is foreword,then frictional force must act backward.
let net force be fn.
so according to the free body diagram,
fn=150-f (say frictional force be f) ........1

fn=ma=50*1.2
Now from this you'll get fn & from equation 1, you'll get f.
 

Related Threads for: What is the magnitude of the frictional force acting on the crate?

Replies
6
Views
7K
Replies
9
Views
14K
Replies
5
Views
4K
Replies
1
Views
594
Replies
4
Views
1K
Replies
4
Views
1K
Replies
56
Views
7K
Replies
4
Views
2K
Top