Momentum

Momentum

Middle School

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Learning Objectives

• Define momentum and learn how to calculate it from mass and velocity.

• Explain the Law of Conservation of Momentum and its use in collisions.

• Tell the difference between perfectly elastic and perfectly inelastic collisions.

• Define impulse and understand its connection to the change in an object's momentum.

Key Vocabulary

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Momentum

A measure of an object's motion, combining its mass and velocity. It indicates how hard it is to stop.

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Conservation of Momentum

The total momentum of objects before a collision is the same as the total momentum after the collision.

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Impulse

A force applied over a specific time that results in a change in an object's momentum.

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Elastic Collision

A collision where objects bounce off each other, and both momentum and kinetic energy are conserved.

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Inelastic Collision

A collision where objects stick together, and only momentum is conserved, while kinetic energy is not.

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What is Momentum?

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Multiple Choice

What two factors are multiplied to determine the momentum of a moving object?

• Mass and velocity

• Force and time

• Mass and acceleration

• Force and velocity

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Conservation of Momentum & Collisions

Elastic Collisions

Inelastic Collisions

Multiple Choice

What is the key difference between a perfectly elastic and a perfectly inelastic collision?

• Momentum is conserved in elastic collisions but not in inelastic ones.

• Objects stick together in elastic collisions and bounce apart in inelastic ones.

• Kinetic energy is conserved in elastic collisions, but not in inelastic collisions.

• Inelastic collisions only happen with objects of equal mass.

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Impulse and Change in Momentum

Multiple Choice

According to the slide, impulse is equal to which of the following?

• The total momentum of the object

• The change in the object's momentum

• The object's mass multiplied by its velocity

• The force applied to an object

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Common Misconceptions about Momentum

Misconception	Correction
Any object with mass automatically has momentum.	An object must be moving to have momentum.
Momentum is not conserved in inelastic collisions.	Momentum is always conserved, but kinetic energy may not be.
A heavier object always has more momentum.	A fast, light object can have more momentum.

Multiple Choice

A large truck has twice the mass of a small car, but the car is moving at twice the speed of the truck. How does the car's momentum compare to the truck's momentum?

• The car has twice the momentum.

• The truck has twice the momentum.

• They have the same momentum.

• The car has four times the momentum.

Multiple Choice

Why is momentum conserved in an inelastic collision even though kinetic energy is not?

• Because the objects stop moving completely after the collision.

• Because kinetic energy is destroyed during the collision.

• Because momentum is transferred between objects, while kinetic energy is converted to other forms like heat and sound.

• Because momentum and kinetic energy are the same physical quantity.

Multiple Choice

An astronaut floating in zero-gravity space throws a heavy tool away from their body. According to the Law of Conservation of Momentum, what is the most likely outcome for the astronaut?

• The astronaut will remain perfectly stationary.

• The astronaut will move in the same direction as the tool.

• The astronaut will move in the opposite direction of the tool.

• The astronaut will begin to spin in place.

Multiple Choice

A baseball catcher pulls their glove backward when catching a fast pitch. In terms of impulse, why does this action reduce the force on the catcher's hand?

• It increases the ball's change in momentum.

• It decreases the time of impact, which increases the force.

• It increases the time of impact, which decreases the force needed to change the ball's momentum.

• It decreases the impulse applied to the ball.

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Summary

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4