Question

A bomb of mass 30 kg at rest explodes into two pieces os masses 18 kg and 12 kg .The velocity of 18 kg mass is 6ms-1.The kinectic energy of the other mass is :

(A) 256J

(B) 486 J

(C) 524 J

(D) 324 J

Answer 1

hope it helps!!!!!!!!!

Answer 2

Answer:

Kinetic energy, 486 J

Explanation:

It is given that, a bomb of mass M = 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg.

Initial velocity of bomb, V = 0

Masses of two pieces, m₁ = 18 kg and m₂ = 12 kg

Velocity of m₁, v₁ = 6 m/s

Using conservation of momentum :

$MV=m_1v_1+m_2v_2$

$M(0)=(18)(6)+12\times v_2$

$v_2=-9\ m/s$

Kinetic energy can be calculated using the following relation :

$E_k=\dfrac{1}{2}m_2v_2^2$

$E_k=\dfrac{1}{2}\times 12\times 9^2$

$E_k=486\ J$

So, the kinetic energy of the other mass is 486 J. Hence, the correct option is (b).