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fatalphysics
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Homework Statement
Block C (m= 4 kg) sits on a frictionless horizontal surface. Block B of (m
= 2kg) sits on top of block C, and is attached to a rope that runs over the massless
pulley as shown in the figure. Block A (m=1 kg) hangs vertically from the rope. With
what horizontal force F must you push Block C so that block A rises with an upward
acceleration of a = 3m/s2? All surfaces are frictionless.
Diagram:
Homework Equations
F=ma
The Attempt at a Solution
Using free body diagrams came up with:
F=mac
T=2ac
T/2=ac
F=maa
T-mg=(3)(1)
T=3+(9.8)(1)
T=12.8 N
(12.8)/2=ac
ac=6.4 m/s2
F=(mc+ma)ac
F=(6)(6.4)
F=38.4 N
Actual answer = 59.8N
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