Question

A stationary mass sudddenly explodes into two fragments, one heavy and another light. Which one has greater kinetic energy and why?

Answer 1

See below.

Explanation:

Conservation of linear momentum

`0 = m_1v_1+m_2 v_2`

Kinetic energies

`E_1=1/2m_1 v_1^2`

`E_2=1/2m_2 v_2^2`

but

`v_2 = -m_1/m_2 v_1` then

`E_2 = 1/2m_2(m_1/m_2)^2v_1^2 = m_1/m_2 E_1`

then we conclude

If `m_1 > m_2 rArr E_2 > E_1`

and vice-versa.