Advertisements
Advertisements
प्रश्न
A boy weighing 350 N climbs up 30 steps, each 20 cm high in 1 minute, Calculate:
- the work done and
- power spent.
Advertisements
उत्तर
Force = weight of body = 350 N
Total distance = h = 30 × 20 = 600 cm
h = `600/100 = 6m`
(i) Work done W = F × h
W = 350 × 6 = 2100 J
(ii) Power spent = `"Work done"/"Time taken" = (30 × "Mg" × "h")/(1 " minute")`
= `((30 × 350 ×20)/100)/(1 " minute")`
= `(2100 J)/(1 " minute")`
= `(2100 J)/(60 " Sec")`
Power spent = 35
APPEARS IN
संबंधित प्रश्न
Draw a simplified diagram of a lemon crusher, indicting of load and effort
When does a force do work?
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.
The work done by a fielder when he takes a catch in a cricket match, is negative. Explain.
State and define the S.I. unit of work.
State two factors on which power spent by a source depends. Explain your answer with examples.
State the principle of moments.
What is a centripetal force?
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes.
How much work each does? Take density of water = 103 kg m-3 and g = 9.8 N kg-1.
State the condition when the work done by the force is positive
