Advertisements
Advertisements
Question
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
Advertisements
Solution
- When a boy with mass m climbs a staircase with a vertical height of h, he works against gravity by using his own weight, F = mg and W = F x h.
- Because displacement occurs in the direction of force, W = mgh in both scenarios.
APPEARS IN
RELATED QUESTIONS
Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.
What is meant by a translational motion? Give one example.
Name the physical quantity whose MKS units are kgm2s-3.
A girl weighting 50 kg climbs up 60 steps each of 20 cm height in 5 minutes. Calculate the power developed.
List any six forms of energy and write a short note on each of them.
A bullet is of mass 'm' g and is moving with a velocity 'v' m/s. Find the kinetic energy of the bullet when
(a) The mass is doubled,
(b) The velocity is tripled.
What should be the characteristic of a source of energy?
A water pump raises 50 kg of water through a height of 25 m in 5s. Calculate the power supplied by the pump (Take: g = 10 N kg−1).
Who is the odd one out?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A wind-mill is lifting water from a well.
