Bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12kg. What is the kinetic energy of other mass?
Answers
The question is incomplete .
Here is the actual question :
A bomb of mass 30 kg at rest explodes into 2 pieces of 18 kg and 12 kg the velocity of 18 kg mass is 6 m/s the K.E of the other mass will be ?
Initial momentum of both them = 0 m/s
Final momentum of 18 kg mass = 6 m/s
By Law of Conservation of mass and energy :
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
Sum of momentums are equal .
0 + 0 = 12× v + 18 × 6
= > 12 v + 108 = 0
= > 12 v = - 108
= > v = - 108/12
= > v = -9
Kinetic energy is given by 1/2 m v²
= > K = 1/2 × 12 × (-9)²
= > K = 6× 81
= > K = 486 J
ANSWER:
The kinetic energy is 486 J
Question:
A bomb of mass 30 kg at rest explodes into 2 pieces of masses 18 kg and 12 kg the velocity of 18 kg mass is 6 m/s the KE of the other mass will be ?
Answer:
486 J
Explanation:
The linear momentum of the exploding part will remain conserved.
Applying Conservation of linear momentum,
m₁u₁ = m₂u₂
here,
m₁ = 18 kg
m₂ = 12 kg
u₁ = 6 m/s
u₂ = ?
u₂ = 18×6÷12 = 9 m/s
u₂ = 9 m/s
Now, The kinetic energy of 12 kg mass
K.E₂ = m₂u₂²/2 = 12×(9)²/2 = 6×81 = 486 J