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?
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
RELATED QUESTIONS
A satellite revolves around the earth in a circular orbit. What is the work done by the force of gravity? Give reason.
Differentiate between work and power.
What is meant by a rotatory motion? Give one example.
State the factors on which moment of force about a point depends.
Work done by a force is equal to the product of ....... and ....
A pump is used to lift 600 kg of water from a depth of 75 m in 10s. Calculate:
- The work done by the pump,
- the power at which the pump works, and
- The power rating of the pump if its efficiency is 40%. (Take g = 10m s-2).
`["Hint" : "Efficiency" = "useful power"/"power input"]`
What do you understand by work? Is work a scalar or a vector quantity?
In the following case write yes, if the work is being done and no if no work is being done.
A man moving on the rough ground.
State the practical unit mainly used in mechanical engineering and write down its equivalent in watt.
Calculate the work done when:
A car is moved on a rough road through 30 m against a frictional resistance of 75 N.
