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संबंधित प्रश्न
An electron emitter must have _____________ work function and ___________ melting point.
State two conditions when no work is done by a force.
How much energy is gained by a box of mass 20 kg when a man, carrying the box waits for 5 minutes for a bus?
If the work done by a force in moving an object through a distance of 20 cm is 24.2 J, what is the magnitude of the force?
Name the physical quantity associated with the 'rate of doing work'.
A bullet is of mass 'm' g and is moving with a velocity 'v' m/s. Find the kinetic energy of the bullet when
(a) The mass is doubled,
(b) The velocity is tripled.
The work done by the heart is 1 Joule per beat. Calculate the power of the heart if it beats 72 times in one.
A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
(i) Calculate the mechanical advantage of the inclined plane. (ii) Calculate the effort applied by the coolie.
(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.
State whether work is done or not, by writing yes or no, in the following case:
A man pushes a wall.
