a man on a bosun chair

OVB

A man is on a bosun chair attached to a frictionless massless pulley and is holding onto the other end of a rope. (at ground level)

a. What is the force he must pull himself up at if he is to move at a constant speed?
Is the set up T + T = mg?

b. If instead the rope is held by someone else, what is the force needed to pull him up at a constant speed?

And is this set up as T = mg?

c. What is the force exerted by the ceiling on the system for both cases?

This one I am lost on since I need to do a free body diagram for each case.

I dont understand why there is such a difference, in essence.

Chi Meson

a and b, you are correct. In a, there are "two tensions" pulling up on the guy in the sling. In b, there is only one tension pulling on the guy.

c:

how many tensions are pulling down on the pulley?

QuantumCrash

Draw a free body diagram from the pulley. That should help.