The kinetic energy of an object of mass` m moving with a velocity of 5 m//s is 25 J. What will be its kinetic energy when its velocity is doubled ? What will be its kinetic energy - when its velocity si increased three times ?

Explanation

K.E of the object = 25 J
Velocity of the object, `v = 5 m//s`
`because` K.E `= 1//2 mv^(2)`
`rArr m = 2 xx K.E//v^(2)`
`rArr m= 2 xx 25//25 = 2 kg`
If velocity is double, `v = 2 xx 5 = 10 m//s`
`:.` K.E (for v = 10 m/s) `= 1//2 mv^(2) =1//2 xx 2 xx 100 = 100 J`
If velocity is tripled, `v = 3 xx 5 = 15 m//s`
`:.` K.E. (for v = 10 m/s) `= 1//2 mv^(2) 1//2 xx 2 xx 225 = 225 J`.