Advertisements
Advertisements
Question
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
Solution
Total height covered = 15 × 20 cm
= 300 cm
= 3 m
Work done = Force × distance
= 700 N × 3 m
= 2100 J
Since the time taken is 5s, the power of the man is
Power = (2100/5) Js−1
= 420 W.
APPEARS IN
RELATED QUESTIONS
Draw a simplified diagram of a lemon crusher, indicting of load and effort
State two factors on which power spent by a source depends. Explain your answer with examples.
Name two places in india where electricity is generated from nuclear power plants.
State the condition when a force produces
(i) linear motion.
(ii) rotational motion, in a body.
A mechanic can open a nut by applying a force of 200 N while using a lever handle of 50 cm length. How long handle is required if he wants to open it by applying a force of only 50 N?
Define one newton. Write the relation between the S. I. unit and the C.G.S. unit of force.
State two conditions for work to be done.
What happens to the power if the time for doing work is reduced from t second to t/10 second?
Relate 1 KWh (kilowatt hour) with joule.
