# Homework Help: Pullies, masses, and acceleration

1. Oct 23, 2009

1. The problem statement, all variables and given/known data
Answer True, False, or Cannot tell to each of the four statements below.

A) If m1 > m2 in the diagram below, then |a2| = g.
http://www.learning.physics.dal.ca/dalphysicslib/Graphics/Gtype09/pulley02.2.gif" [Broken]

B) In the diagram below, a1y = a2y.
http://www.learning.physics.dal.ca/dalphysicslib/Graphics/Gtype09/pulley02.2.gif" [Broken]

C) The diagram below shows two blocks, 1 and 2, at rest, connected to a rope and pulley system. There is friction between the blocks, but block 2 rests on a frictionless surface. An external force Fext is applied; the tension in the rope is T and the frictional force is F. The frictional force on block 2 points right.
http://www.learning.physics.dal.ca/dalphysicslib/Graphics/Gtype09/pulley02.4.gif" [Broken]

D) Block 1 rests on a frictionless table. In case A, a 10 N weight is attached; in case B, a 10 N force is applied to the rope. Block 1 accelerates faster in case B.
http://www.learning.physics.dal.ca/dalphysicslib/Graphics/Gtype09/pulley02.3.gif" [Broken]

3. The attempt at a solution

A) I think this one would be true because all objects fall toward the earth with an acceleration of g, so m2 would be pulled up with an acceleration of g.
B) I don't know about this one. Maybe it's cannot tell because we don't know the mass of each of the masses?
C) I think this one is true because because when m2 moves to the right, m1 would move to the left so its frictional force would be to the right.
D) I'm really unsure about this one. Is there a difference between a 10 N weight and 10 N of tension? I didn't think there was.

I keep getting this question wrong, so if someone could help me, that would be great. <:

Last edited by a moderator: May 4, 2017
2. Oct 23, 2009