Question

A man and his son run to the top of a hill and stop. The mass of a man is greater than the mass of the boy. a) While they are both running at the same speed who has more kinetic energy? *Would it be possible for them to have the same amount of kinetic energy? How?

Answer 1

a)

let mass of man = M1

let mass of boy = M2

given M1 > M2

let assume both man and boy running at speed V m/s

kinetic energy ( K ) = ½ MV²

for man , K1 = ½ M1 V²

for boy , K2 = ½ M2 V²

we know , M1 > M2

so ,, K1 > K2

so , Man has more kinetic energy than boy .

b)

if K1 = K2

then , ½ M1 V² = ½ M2 V²

M1 = M2

for same kinetic energy there mass will be same .

or

for same kinetic energy their velocity will be different ,

let assume ,

man velocity = V1

boy velocity = V2

if K1 = K2

½ M1 V1² = ½ M2 V2 ²

( M1 / M2 ) = ( V2 / V1 ) ²

Explanation:

HOPE IT WILL BE HELPFUL.