A bomb of mass `3.0 kg` explodes in air into two pieces of masses `2.0 kg` and `1.0 kg`. The smaller mass goes at a speed of `80 m//s`. The total energy imparted to the two fragments is :

Options

A. 1.07 kJ
B. 2.14 kJ
C. 2.4 kJ
D. 4.8 kJ

Answer

D

Explanation

`m_1v_1 = m_2 v_2 implies 1 xx80 = 2 xxv_2 implies v_2 = 40 m//s`
Total energy –
`=1/2 m_1v_1^2 + 1/2 m_2v_2^2 =1/2 xx 1 xx (80)^2 +1/2 xx 2 xx (40)^2`
= 4800 J = 4.8 kJ.