A machine of efficiency 80% is used to raise a body of mass 75kg through a vertical height of 3m in 30s. Calculate the power input. (g = 10ms-2)

Mayor.com

5 years ago

E= power output / Power input
E=80% not 8% take note ✔️
Power output= mgh/t, substituting these u will get 75W
Power input =?
80=75×100/ power input
Power input = 7500/80
Power input = 93.75.


If 8 is the efficiency the the power input will be 937.5W which is not in the option ✅✅

Ella2325

4 months ago

ok

Gofgeo

2 years ago

The question clearly needs explanations since it deals with calculations but there is none

peay

2 years ago

=937.8

peay

2 years ago

75*3*10=2250/30=75/8%=937.5
Not 93.8