Finding ratio of masses of two blocks

  • #1
410
11

Homework Statement


  1. Two crates are stacked on top of each other on a horizontal floor. The coefficient of static friction between Box A and Box B is 0.6. The coefficient of static friction between Box A and the floor is 0.2. A force of 100 N is applied parallel to the floor on Box B. The boxes move together along the floor. The ratio of the mass of Box A to Box B is possibly
  1. 1) 5:1
  2. 2) 5:2
  3. 3) 4:1
  4. 4) 3:1
  5. 5) 1:2

Homework Equations



none so far

The Attempt at a Solution


Hi people. I was trying to figure out how to solve this problem, but I do not even have any hints of an idea so far. Could anyone please help me gets started?
Thanks in advance!
 

Answers and Replies

  • #2
CWatters
Science Advisor
Homework Helper
Gold Member
10,532
2,298
For the boxes to move friction between A and B must be greater than between A and the floor.

Write equations for both and set up that inequality. Rearrange.
 
  • #3
410
11
For the boxes to move friction between A and B must be greater than between A and the floor.
Why is this so?
 
  • #4
CWatters
Science Advisor
Homework Helper
Gold Member
10,532
2,298
Think about how the applied force is transmitted to the lower box.

Drawing a FBD for the lower box may help.
 
  • #5
CWatters
Science Advisor
Homework Helper
Gold Member
10,532
2,298
You posted one or two similar questions and they all depend on you understanding the forces acting on the lower box.
 

Related Threads on Finding ratio of masses of two blocks

Replies
3
Views
17K
Replies
1
Views
2K
  • Last Post
Replies
1
Views
8K
Replies
2
Views
3K
Replies
2
Views
14K
Replies
9
Views
3K
  • Last Post
Replies
1
Views
1K
Top