Questions and Answers
A moving car has momentum. If it moves twice as fast, momentum is ________ as much.
twice
Two cars, one twice as heavy as the other, move down a hill at the same speed. Compared to the lighter car, the momentum of the heavier car is __________ as much.
twice
The recoil momentum of a cannon that kicks is (more than) (less than) (the same as) the momentum of the cannonball when it fires.
If a man firmly holds a cannon and it fires, then the momentum of the cannonball is equal to the recoil momentum of the (cannon ball alone) (cannon-man system) (man alone).
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Compared to the force that acts on the bug when it splatters on the bus window, how much force acts on the bus? (More) (same) (less)
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The time of impact is the same for both the bug and the bus. Compared to the impulse on the bug, this means the impulse on the bus is (more) (same) (less).
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Although the momentum of the bus is very large compared to the momentum of the bug, the change in momentum of the bus compared to the change of the momentum of the bug is (more) (same) (less).
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Which undergoes the greater acceleration? (Bus) (both the same) (bug)
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Which therefore suffers the greater damage? (Bus) (both the same) (bug)
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Granny mass: 80kg, Granny speed: 3m/s, Granny momentum: ______. Ambrose's mass: 40kg, Ambrose's speed: 0m/s, Ambrose's momentum: _______. Total momentum: ________.
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After the collision, does Granny's speed increase or decrease?
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After the collision, does Ambrose's speed increase or decrease?
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After a collision, what is the total mass of Granny and Ambrose? Granny = 80kg, Ambrose = 40kg.
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After the collision, what is the total momentum of Granny and Ambrose? Granny's momentum = ______, Ambrose = 0kgm/s.
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Use the conservation of momentum law to find the speed of Granny and Ambrose together after the collision.
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Study Notes
Momentum Concepts
- Momentum of an object is determined by its mass and velocity; a moving car with double the speed has double the momentum.
- Heavier objects exhibit greater momentum when moving at the same speed as lighter objects; a car twice as heavy has twice the momentum of a lighter car at the same speed.
Recoil and Systems
- The recoil momentum of a cannon is equal to the momentum of the cannonball when fired; they are the same due to conservation of momentum.
- In a cannon-man system, the total momentum of the system is conserved; when the cannonball is fired, the momentum gained by the cannonball equals the recoil momentum of the cannon and man together.
Impulse and Forces
- When a bug hits a bus, the force acting on both the bug and the bus is the same; however, they experience different effects due to their differing masses.
- The impulse experienced by the bug and the bus is the same due to the equal time of impact, despite the bus having much larger momentum.
- The change in momentum is the same for both the bug and the bus during the impact event.
Acceleration and Damage
- Due to its smaller mass, the bug undergoes greater acceleration compared to the bus when the two collide, resulting in severe damage to the bug rather than the bus.
Collision Scenarios
- Granny has a mass of 80 kg and a speed of 3 m/s, resulting in a momentum of 240 kg·m/s; Ambrose has a mass of 40 kg and is initially stationary, giving him a momentum of 0 kg·m/s.
- Total momentum before collision is the sum of both individuals: 240 kg·m/s for Granny and 0 kg·m/s for Ambrose, totaling 240 kg·m/s.
- Following a collision, Granny's speed decreases while Ambrose’s speed increases.
Post-Collision Calculations
- The combined mass of Granny and Ambrose post-collision is 120 kg (80 kg + 40 kg).
- The total momentum after the collision remains at 240 kg·m/s.
- Using the conservation of momentum, the new speed of Granny and Ambrose together after the collision is calculated to be 2 m/s.
Studying That Suits You
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Description
Test your understanding of momentum with these flashcards based on Chapter 8 of physics. Each card presents a scenario related to momentum, designed to reinforce your knowledge of this key concept in physics. Perfect for reviewing before an exam or quiz.
