Advertisements
Advertisements
प्रश्न
Advertisements
उत्तर
K.E, K = `1/2 mv²
if speed is incresed four times
K.E,K' = `1/2` m(4v)²
or K' = 16 x `1/2` mv² = 16K
thus K.E becomes sisxteen times
APPEARS IN
संबंधित प्रश्न
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A sailboat is moving due to wind energy.
Define work.
A body of mass 60 kg has the momentum 3000 kgm/s-1. Calculate: the speed of the body.
State the amount of work done by an object when it moves in a circular path for one complete rotation. Give a reason to justify your answer.
How long should an electric motor, of power 2 H.P. operate, so as to pump 5 m3 of water from a depth of 15m. [Take g = 10 N kg−1]
A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
________ is said to be done when a force is acting on it.
