Pick choice-A .
Weight of a mass = (mass) x (gravity)
Earth gravity = (9.8 m/s )
Weight of a mass = (9.8 x mass) Newtons
Work = (force) x (distance)
Power = (work done) / (time to do the work)
Weight of this mass = (8.5 kg) x ( 9.8 m/s ) = 83.3 Newtons
Work to lift it 1 meter = (83.3 N) x (1 m) = 83.3 Joules
Power to lift it 1 meter/sec = 83.3 Joule/sec = 83.3 watt
Power to lift it ' v ' meters/sec = 83.3v watts
In this problem ...
83.3 v watts = 60 watts
v = 60/83.3 m/s
v = 0.72 m/s
