Momentum Calculations

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Questions and Answers

What is the formula used to calculate momentum?

Momentum = mass x velocity (correct)

Velocity = distance / time

Acceleration = change in velocity / time

Force = mass x acceleration

An object can have momentum when it is at rest.

False

What does the term 'vector' refer to in physics?

A physical quantity that has both magnitude and direction

The momentum of an object is zero when it is __________.

at rest Signup and view all the answers

Match the following objects with their respective masses and speeds:

Lorry = 7,500 kg at 25 m/s Ice skater = 60 kg at 15 m/s Signup and view all the answers

What happens to the total momentum in a closed system when an event occurs?

It remains the same. Signup and view all the answers

Momentum is conserved in collisions and explosions.

True Signup and view all the answers

What term describes a system not influenced by external forces?

closed system Signup and view all the answers

A cannon with a mass of 96 kg fires a cannonball at _______ m/s.

120 Signup and view all the answers

Match the types of events with their descriptions:

Collision = When two objects meet and interact Explosion = When parts of a system separate and move apart Closed System = A system unaffected by external forces Conservation of Momentum = Total momentum remains the same before and after an event Signup and view all the answers

What will happen to the momentum of the cannon when it fires a cannonball?

The cannon gains backward momentum. Signup and view all the answers

The total momentum of the cannon and cannonball before firing is zero.

True Signup and view all the answers

When two trolleys collide in a closed system, what principle can be used to calculate their combined velocity after the collision?

principle of conservation of momentum Signup and view all the answers

What is momentum primarily a combination of?

Mass and velocity Signup and view all the answers

Increasing the time taken for a collision can increase the rate of change of momentum.

False Signup and view all the answers

What units are used to quantify force?

Newtons Signup and view all the answers

The equation to calculate force when a change in momentum occurs is _______ = mass × acceleration.

force Signup and view all the answers

Match the car safety features with their functions:

Seatbelts = Secure occupants during a collision Airbags = Inflate to cushion impact Crumple zones = Absorb energy by deforming Anti-lock brakes = Prevent skidding during braking Signup and view all the answers

Study Notes

Momentum

Momentum is a quantity relating to a moving object, calculated by multiplying mass and velocity.
Momentum is a vector quantity, meaning it has both magnitude and direction.
An object at rest has zero momentum.
Momentum increases with increasing velocity.
Momentum can be thought of as a combination of mass and velocity.
Momentum helps explain some of the most important interactions in nature.
The total momentum before an event equals the total momentum after the event (conservation of momentum).
A closed system is not affected by external forces.
Momentum is conserved in collisions and explosions.
Conservation of momentum explains recoil in guns/cannons.
Force is related to the rate of change of momentum (force = rate of change of momentum).

Calculating Momentum

Momentum (p) = mass (m) × velocity (v)
Units: kg m/s (kilograms meters per second)

Example Calculations

Lorry:
- Mass = 7,500 kg
- Velocity = 25 m/s (south)
- Momentum = 7,500 kg × 25 m/s = 187,500 kg m/s (south)
Ice Skater:
- Mass = 60 kg
- Velocity = 15 m/s
- Momentum = 60 kg × 15 m/s = 900 kg m/s

Conservation of Momentum

The total momentum of a system remains the same.

Collisions

When two objects meet and interact.
During a collision there is a change in momentum; the force of the collision is related to the rate of change of momentum.

Explosions

When parts of a system separate and move apart.

Example: Cannon & Cannonball

Before firing (event), total momentum = 0 kg m/s (neither moving).
After firing,total momentum = 0 kg m/s (momentum of cannon and cannon ball in opposite directions).

Example Calculations: Trolleys/ Explosions ( using conservation of momentum)

Momentum is calculated for trolleys/ cannon and cannon ball before and after collision/ explosion.
The velocity of the combined trolleys/cannon ball and cannon after collision can be calculated using conservation of momentum.
Positive values for velocity indicate direction.
A cannon ball of mass 4.0 kg is fired from a stationary 96 kg cannon at 120 m/s.
The velocity of the cannon immediately after firing can be calculated using conservation of momentum.

Force and Momentum

Force = mass × acceleration
Force is equivalent to the rate of change of momentum
Car safety features (seatbelts, airbags, crumple zones) increase the time taken for a collision, decreasing the rate of change of momentum and the force of the collision.
Crumple zones are areas of a car designed to deform upon impact.

Example Calculation: Car Acceleration

Mass = 1,500 kg
Initial velocity = 0 m/s
Final velocity = 30 m/s
Time taken = 20 seconds
Calculate the force acting on the car using the relationship force = mass × change in velocity / time taken

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Description

This quiz focuses on the concept of momentum, including its definition, properties, and calculation methods. Explore examples that illustrate how to calculate momentum for different objects using mass and velocity. Test your understanding of this fundamental physics topic.