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In Figure 7-48 (see attatched), a cord runs around two massless, frictionless pulleys. A canister with mass m = 11 kg hangs from one pulley, and you exert a force F on the free end of the cord:
(a) What must be the magnitude of F if you are to lift the canister at a constant speed?
(b) To lift the canister by 1.9 cm, how far must you pull the free end of the cord?
(c) During that lift, what is the work done on the canister by your force (via the cord)?
(d) What is the work done on the canister by the gravitational force on the canister?
I don't like pulleys. Can I just pretend that the applied force acts directly on the canister and points straight up? I'm fairly certain that's OK for parts (a) and (c), but I'm not so sure about part (b).
(a) What must be the magnitude of F if you are to lift the canister at a constant speed?
(b) To lift the canister by 1.9 cm, how far must you pull the free end of the cord?
(c) During that lift, what is the work done on the canister by your force (via the cord)?
(d) What is the work done on the canister by the gravitational force on the canister?
I don't like pulleys. Can I just pretend that the applied force acts directly on the canister and points straight up? I'm fairly certain that's OK for parts (a) and (c), but I'm not so sure about part (b).