A boy of mass 52 kg jumps with a horizontal velocity of 2 m/s onto a stationary cart of mass 3 kg. The cart is fixed with frictionless wheels. Which one of the following would be the speed of the cart?
This questions was previously asked in
2022 NDA -1 GAT
2.15 m/ s
Incorrect Answer1.51 m/ s
Incorrect Answer2.51 m/ s
Incorrect AnswerExplanation:
- A boy with a mass of 52 kg jumps onto a stationary cart weighing 3 kg.
- The boy's horizontal velocity is 2 m/s.
- We need to find the speed of the cart after the boy jumps onto it.
- Use the conservation of momentum: initial momentum = final momentum.
- Initial momentum = mass of boy × velocity of boy = 52 kg × 2 m/s = 104 kg·m/s.
- Final momentum = (mass of boy + mass of cart) × velocity of boy and cart.
- Set them equal: 104 kg·m/s = (52 kg + 3 kg) × speed.
- Solve for speed: 104 kg·m/s = 55 kg × speed ? speed = 104/55 m/s = 1.89 m/s.
Correct Answer: Option 2, 1.89 m/s
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By: Parvesh Mehta