The third floor of a house is 8 m above street level. How much work must a pulley system do to lift a 150kg oven at a constant speed to the third floor

The pulley system doesn't do any work. The work is done by

the machine, the man, or the horse that pulls one end of the rope

out of the pulley system. The pulley system just passes the work

through itself, to lift the load.

The work required to lift anything to a certain height is the amount

of gravitational potential energy it'll have when it gets there.

P. E. = (mass) x (gravity) x (height)

= (150 kg) x (9.81 m/s²) x (8 m)

= 11,772 kg-m / s²-m

= 11,772 kg-m/s²

= 11,772 Joules.

1. 150*9.81*8 j

2. 175=m*9.81*.300

3. 80*10 j