Advertisements
Advertisements
Question
A man having a box on his head, climbs up a slope and another man having an identical box walks the same distance on a levelled road.
Who does more work against the force of gravity and why?
Advertisements
Solution
Man having a box on his head who climbs up a slope does more work against the force of gravity because he has more potential energy by virtue of his position i.e., height.
As, P.E. = W.D. = F × S
= mg × h
APPEARS IN
RELATED QUESTIONS
A coolie X Carrying a load on his head climbs up a slope and another coolie Y carrying the identical load on his head move the same distance on a frictionless horizontal platform. Who does more work? Explain the reason.
Differentiate between work and power.
A boy weighing 350 N climbs up 30 steps, each 20 cm high in 1 minute, Calculate:
- the work done and
- power spent.
A body of mass m is moving with a uniform velocity u. A force is applied on the body due to which its velocity changes from u to v. How much work is being done by the force?
State the factors on which moment of force about a point depends.
What do you mean by equilibrium of a body?
In which one of the following cases is the work done more? When the angle between the direction of motion and that of the force is (i) 90° (ii) 0°.
A force F when acts on a body, displace it by a distance d in a direction at an angle θ with the direction of the force. Write down the expression for the work done by the force.
A coolie carrying a load on his head and moving on a frictionless horizontal platform does no work. Explain the reason why.
The world record for weight lifting was held by Sergei Didyk of the USSR. He lifted 261 kg to a height of 2.3 m in 4s; find:
(a) Weight lifted by him
(b) Work done by him
(c) Power developed by him. (g = 10m/s2)
