Static Friction Video Lessons

Concept

# Problem: Part A.) Six boxes held at rest against identical walls.Rank the boxes on the basis of the magnitude of the normal force acting on them.Rank from largest to smallest. To rank items as equivalent, overlap them.1.)130N---&gt;7kg2.)150N---&gt;1kg3.)150N---&gt;7kg4.)120N---&gt;3kg5.)140N---&gt;5kg6.)140N---&gt;3kg(Since the boxes are at rest, Newton's 2nd law dictates that the horizontal forces on each box must add up to zero. You can use this information to determine the normal forces. If two boxes are both pushed against the wall by the same force, then they should experience the same normal force.)Part B.) Rank the boxes on the basis of the frictional force acting on them.Rank from largest to smallest. To rank items as equivalent, overlap them.1.)130N---&gt;7kg2.)150N---&gt;1kg3.)150N---&gt;7kg4.)120N---&gt;3kg5.)140N---&gt;5kg6.)140N---&gt;3kg

###### FREE Expert Solution
Let the x-axis point horizontally and the y-axis point vertically:

Part A

Assume the Force is applied towards the left, and the normal force acts to the right.
ΣFx = ma

N - Fapplied = 0

N = Fapplied

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###### Problem Details
Part A.) Six boxes held at rest against identical walls.
Rank the boxes on the basis of the magnitude of the normal force acting on them.
Rank from largest to smallest. To rank items as equivalent, overlap them.

1.)130N--->7kg
2.)150N--->1kg
3.)150N--->7kg
4.)120N--->3kg
5.)140N--->5kg
6.)140N--->3kg

(Since the boxes are at rest, Newton's 2nd law dictates that the horizontal forces on each box must add up to zero. You can use this information to determine the normal forces. If two boxes are both pushed against the wall by the same force, then they should experience the same normal force.)

Part B.) Rank the boxes on the basis of the frictional force acting on them.
Rank from largest to smallest. To rank items as equivalent, overlap them.

1.)130N--->7kg
2.)150N--->1kg
3.)150N--->7kg
4.)120N--->3kg
5.)140N--->5kg
6.)140N--->3kg