Question

A man uses a pully system to raise 150 kg load to a height of 10 m. It he exerts a force on the rope of 50 N through a distance of 35 m to accomplish the work in 7 seconds, the average power used and efficiency of the machine are​

Answer 1

Answer:

75

Explanation:

Correct option is

B 75

Height lift was h=3m

Work done by the force is W=Fd=250×12=3000Joule

Work against the gravity i.e. increase in potential energy of the mass is E=mgh=75×10×3=2250Joule

so efficiency will be η×100= W/E×100% = 75%