Advertisements
Advertisements
प्रश्न
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.
Advertisements
उत्तर
K.E of the bullet = `1/2` mv2
(a) If the mass is doubled,
K.E' = `1/2`(2m) v2 = `2 xx 1/2`mv2 = 2K.E
`"K.E"/"K.E" = 2/1`
(b) If the velocity is tripled,
K.E = `1/2` m(3v)2 = 9 x `1/2` mv2
`"K.E"/"K.E" = 9/1`
APPEARS IN
संबंधित प्रश्न
Give reasons for the following. No work is done if a man is pushing against a wall.
A man lifts a mass of 20 kg to a height of 2.5 m. Assuming that the force of gravity on 1 kg mass is 10 N, find the work done by the man.
When do we say that work is done? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it.
A boy pulls a box up to 10 m with a force of 5 kgf. Calculate the work done by him.
Fill in the boxe to show the corresponding energy transformation.
Write the two main conditions are needed for work to be done?
