Advertisements
Advertisements
Question
State the condition when the work done by a force is positive. Explain with the help of examples.
Advertisements
Solution
If the displacement of the body is in the direction of force, then work done is positive.
Hence, W= F × S
For example: A coolie does work on the load when he raises it up against the force of gravity. The force exerted by coolie (=mg) and displacement, both are in upward direction.
APPEARS IN
RELATED QUESTIONS
The work done by a fielder when he takes a catch in a cricket match, is negative. Explain.
kWh is the unit of ______.
A man spends 7.4 KJ energy in displacing a body by 74 m in the direction in which he applies force in 2.5 s. Calculate the force applied.
State the condition when the work done by a force is negative. Explain with the help of examples.
1 kWh = ______ J.
It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B of same mass does the same in 15 s. Compare the power developed by the persons A and B.
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.
A coolie carrying a load on his head and moving on a frictionless horizontal platform does no work. Explain the reason why.
State the C.G.S. unit of work. How it is related to its S.I. unit?
