Advertisements
Advertisements
प्रश्न
No work is done by a force if the body
विकल्प
moves in direction of force
does not move
moves in opposite direction
none of the these
Advertisements
उत्तर
does not move
APPEARS IN
संबंधित प्रश्न
The S.I. unit of energy is .............
Write the formula for the work done on a body when a force acts on the body in the direction of its displacement. Give the meaning of each symbol which occurs in the formula.
The work done by a force acting obliquely is given by the formula : W = F cos θ ✕ s. What will happen to the work done if angle θ between the direction of force and motion of the body is increased gradually? Will it increase, decrease or remain constant.
Name five appliances or machines which use an electric motor.
(a) Define power and name its unit.
(b) A girl weighting 50 kg climbs up 60 steps each of 20 cm height in 5 minutes. Calculate the power developed.
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).
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
An engine is pulling a train.
