Advertisements
Advertisements
Question
A machine raises a load of 750 N through a height of 16 m in 5 s. calculate:
- energy spent by machine,
- power at which the machine works.
Solution
- Energy spent by machine or work done = F × S
Work, W = 750 × 16 = 12000J - Power spent = `"work done"/"time taken " = "12000j"/"5s" = 2400 "w"`
APPEARS IN
RELATED QUESTIONS
Power spent by a body depends on the time for which it does work.
No work is done by a force if the body
Give reasons for the following A teacher moving around in the class is doing work but a child standing and reading a book is not doing any work.
A boy of mass 40 kg climbs up the stairs and reaches the roof at a height 8 m in 5 s. Calculate:
- the force of gravity acting on the boy,
- the work done by him against the force of gravity,
- the power spent by boy. (Take g = 10 m s-2)
How much work is done when a body of mass m is raised to a height h above the ground?
What should be the angle between the direction of force and the direction of motion of a body so that the work done is zero?
Is the motion of moon around the earth in circular path an accelerated motion?
A boy does work when he pushes against a brick wall. (yes/no).
Distinguish between work and power.
Fill in the boxe to show the corresponding energy transformation.
Fill in the boxe to show the corresponding energy transformation.
An electric motor pump is 60% efficient and is rated 2.5 H.P. Calculate the maximum load it can lift through a height of 10m in 8 sec. (1 H.P. = 750 W).
A bucketful of water is to be drawn from a well ______ will be done when a ______ is applied to do this because there will be a ______ of water.
(displacement, work, force)
A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is ______.
