Advertisements
Advertisements
Question
A man lifts a mass of 20 kg to a height of 2.5 m. Assuming that the force of gravity on 1 kg mass is 10 N, find the work done by the man.
Advertisements
Solution
Mass = 20 kg h = 2.5 m
Force of gravity on a mass of 1 kg = 10 N
Force of gravity on a mass of 20kg
F = mg = 20 × 10 = 200 N
Work done in lifting the mass to height h = 20 m is
W = F × h
= 200 N × 2.5 m
= 200 × 25/10 =500 J
APPEARS IN
RELATED QUESTIONS
Is work a scalar or a vector quantity?
A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s−2, the work by her after climbing 2 m will be :
Why is the work done on an object moving with uniform circular motion zero?
An electric motor drives a machine which lifts a mass of 4 kg through a height of 10 m in 5 s at a constant speed. Assuming g = 10 ms-2, calculate
(i) the amount of work done, (ii) the power of the machine.
If an electric bulb of 100 watt is lighted for 2 hours, how much electric energy would be consumed?
State the energy changes which take place when A toy car with a wound spring moves on ground.
Give an example
Electrical energy changes to heat energy.
Who is the odd one out?
