Physics 30

A system containing a frictionless pulley is described in the diagram on the right (the 2.0 kg box is on the floor while the 3.0 kg box is 0.5m high) . If this system is released, what will be the momentum of:


A. the 2.0 kg box when the 3.0 kg box hits the floor?

b. the 3.0 kg when it hits the floor?

asked by Mona
  1. a. I would work this by energy.
    mass2 gains PE, and gains KE, the mass3 loses PE, and gainsKE. the net change in total energy is zero.
    Both masses will have the same velocity.

    1/2 2 V^2+2g*.5-3g*.5+1/2 3 v^2=0

    v^2(1+3/2)=-g+1.5g
    v= sqrt (.5g*2/3)=sqrt(g/3)

    check that.

    posted by bobpursley

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