Question about Kinetic Force


by pope17
Tags: force, friction, kinetic, physics, weight
pope17
pope17 is offline
#1
Nov13-10, 06:02 PM
P: 1
1. The problem statement, all variables and given/known data

A box has a weight of 150N and is being pulled across a horizontal floor by a force that has a magnitude of 110N. The pulling force can point horizontally, or it can point above the horizontal at an angle (?). When the pulling force points horizontally, the kinetic frictional force acting on the box is twice as large as when the pulling force points at the angle (?).

2. Relevant equations

Find (?)

3. The attempt at a solution

I set up my equation to be 2(150)=150 - 110sin43.
...which is not right.
any help would be greatly appreciated :)
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PhanthomJay
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#2
Nov13-10, 06:41 PM
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pope 17, welcome to Physics Forums!

How did you determine that the angle is 43 degrees, if your equation was set up incorrectly?

Re-wording the problem, note that when the pulling force acts at an angle , the kinetic friction force is 1/2 the kinetic friction force when the pulling force acts horizontally.


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