Questions and Answers
The momentum of an object is defined as the object's:
Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?
The momentum change of an object is equal to the:
Compared to the force on the ball, the force on the launcher is:
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If a freight train rolls at the same speed but had half as much mass, its momentum would be:
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Momentum and velocity share a/an:
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When would a small car have more momentum than a large truck?
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A 5-kg ball is thrown at 4 m/s. What is the ball's momentum?
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A 10.0-kg ball has a momentum of 5.0 kg×m/s. What is the ball's speed?
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A collision is considered elastic if:
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A rubber ball with a mass of 0.30 kg is dropped onto a steel plate. The ball's velocity just before the impact is 4.5 m/s and just after is 4.2 m/s. What is the change in the ball's momentum?
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Using the rubber ball from question #11, what is the ball's impulse after impact if the momentum was -0.09 kg×m/s?
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An object of 10 kg mass is initially at rest. A constant horizontal force of 20 N is applied to it for a time interval of 5 seconds. The impulse given to the object is:
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How much force is necessary to stop a bowling ball with a mass of 8 kg traveling at 12 m/s in 3 seconds?
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How long was the jack hammer being used if a force of 150 N was exerted on it with a mass of 75 kg that moves with a velocity of 20 m/s?
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Compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles per hour has:
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The momentum of a system is conserved only when:
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Ms. Blair is driving her car due east at velocity of 10 m/s. If Ms. Blair has a mass of 50 kg and her car has a mass of 1000 kg, what is the momentum of Ms. Blair and her car?
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A ball is moving at 6.0 m/s and has a momentum of 24.0 kg×m/s. What is the ball's mass?
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A 8 kg blob of clay moving horizontally at 3 m/s hits a 2 kg blob of clay at rest. What is the velocity of the two blobs stuck together immediately after the collision?
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Which surface allows more time of impact and reduces the force on the object?
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A monster truck that has a mass of 3000 kg is speeding down the highway at a speed of 100 m/s. It collides into a stationary parked car that has a mass of 200 kg. After the collision, the car sticks to the monster truck. What is the velocity of the 2 vehicles after the collision?
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If the momentum of an object changes and its mass remains constant,
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Momentum is considered a vector quantity because it has both:
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The reason padded dashboards are used in cars is that they:
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If a freight train rolls at the same speed but had twice as much mass, its momentum would be:
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In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because:
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When would a small car have more momentum than a large truck?
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Study Notes
Momentum Basics
- Momentum is defined as mass times velocity.
- Larger mass results in greater momentum at the same velocity; thus, a large truck moving at 30 mph has more momentum than a small truck at the same speed.
Impulse and Momentum Change
- The change in momentum is equal to the impulse acting on an object.
- Forces on interacting objects (e.g., a launcher and a ball) are equal in magnitude and opposite in direction.
Momentum and Mass Relationships
- Doubling an object's mass while maintaining the same speed doubles its momentum.
- Inversely, halving the mass results in halved momentum if speed remains constant.
Directly Proportional Relationships
- Momentum and velocity have a directly proportional relationship: as one increases, so does the other.
Calculating Momentum
- Momentum (p) can be calculated using the formula p = mass * velocity.
- Example: A 5-kg ball thrown at 4 m/s has momentum of 20 kg·m/s.
Collision Types
- An elastic collision retains shape, shows no lasting deformation, and generates no heat post-collision.
- Impulse experienced by an object can be calculated based on the change in momentum; if momentum is -0.09 kg·m/s, the impulse is also -0.09 kg·m/s.
Forces and Stopping
- To stop an object, the required force can be calculated by considering mass and speed over time. Example: stopping an 8-kg bowling ball at 12 m/s requires 32 N over 3 seconds.
System Momentum Conservation
- Momentum of a system is conserved only when there is no net external force acting on it.
- If an object’s momentum changes but mass remains constant, then it is experiencing a change in velocity and therefore, acceleration due to an applied force.
Composite Momentum Calculations
- When two objects collide and stick together, their combined velocity post-collision can be calculated using the principle of momentum conservation.
- Example: A monster truck and a stationary car colliding, moving together afterward, results in a velocity of 93.75 kg·m/s.
Importance of Time in Collisions
- Padded surfaces and extending the time of impact reduce the force of impact experienced by objects (e.g., using padded dashboards in cars).
- A baseball player's hand moving backward when catching reduces the force due to an increase in time of impact.
Characteristics of Momentum
- Momentum is a vector quantity, possessing both magnitude and direction which is essential in analyzing collisions and motion.
Unique Situations
- A small car can have more momentum than a large truck only if the truck is at rest while the car is in motion.
- The velocity change after a collision can dramatically impact the momentum of both objects involved.
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Description
This quiz covers the fundamentals of momentum including its definition, relationship with mass and velocity, and the concept of impulse. You'll encounter calculations and understand how changes in mass and speed affect momentum. Test your knowledge of collision types and directly proportional relationships in physics.
