An internal explosion breaks an object, initially at rest, into two pieces: A an

Question

An internal explosion breaks an object, initially at rest, into two pieces: A and B. Piece A has 2.4 times the mass of piece B. The energy of 7200 J is released in the explosion.

Part A

Determine the kinetic energy of piece A after the explosion.

Express your answer to two significant figures and include the appropriate units.

PART B

Determine the kinetic energy of piece B after the explosion.

Express your answer to two significant figures and include the appropriate units.

An internal explosion breaks an object, initially at rest, into two pieces: A and B. Piece A has 2.4 times the mass of piece B. The energy of 7200 J is released in the explosion.

Part A

Determine the kinetic energy of piece A after the explosion.

Express your answer to two significant figures and include the appropriate units.

PART B

Determine the kinetic energy of piece B after the explosion.

Express your answer to two significant figures and include the appropriate units.

Explanation / Answer

Let the masses are m & 2.4m, Let the respective velocities are v1 & v2 after the explosion. By the law of momentum conservation:-
=>m1u1 + m2u2 = m1v1 + m2v2
=>0 + 0 = mv1 + 2.1mv2
=>v1 = -2.4v2 ---------------------(i)
Thus ratio of KE1:KE2 = 1/2mv1^2:1/2(2.1m)v^2
=>KE1/KE2 = 2.1/1 --------------(ii)
But KE1 + KE2 = 7200
=>2.4KE2 + KE2 =7200
=>KE2 = 2117.64 J
=>KE1 = 5058.2 J

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