Momentum with a worked rugby example, conservation of momentum in a tackle, impacts and catching, impulse with a worked sprint start, scalars and vectors, force–time graphs for a sprinter, and the shot putter's impulse.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What is momentum?

Key term

What is the momentum of an 80 kg rugby player running at 7 m s⁻¹?

Key term

What is the conservation of momentum?

Questions from this subtopic

Each one with the model answer underneath.

1
What is momentum?
Model answer
Momentum is the quantity of motion a body has. Momentum equals mass multiplied by velocity and is measured in kg m s⁻¹.
2
What is the momentum of an 80 kg rugby player running at 7 m s⁻¹?
Model answer
The momentum is 560 kg m s⁻¹. The working is 80 kg × 7 m s⁻¹ = 560 kg m s⁻¹.
3
What is the conservation of momentum?
Model answer
The total momentum before a collision equals the total momentum after it, provided no external force acts. Momentum is transferred between the colliding bodies.
4
A 100 kg forward running at 5 m s⁻¹ is held in a tackle by a stationary 90 kg defender, and the two move off together. How fast do they move?
Model answer
The pair move off at about 2.6 m s⁻¹. The momentum before is 100 kg × 5 m s⁻¹ = 500 kg m s⁻¹. The shared velocity is 500 ÷ 190 kg = 2.6 m s⁻¹.
5
What is meant by an impact in sport?
Model answer
An impact is a collision in which a large force acts for a very short time. A bat striking a ball, a tackle and a landing are examples.
6
How can the force of an impact be reduced?
Model answer
The time over which the momentum changes can be increased. Bent knees on landing, crash mats and padding all extend the time and lower the force.

See the rest and revise

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book

2Open book

3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Health, Fitness and an Active Lifestyle

Short-Term Responses to Exercise

Long-Term Adaptations to Exercise

Fitness Testing and Components of Fitness

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

Leadership is seen as .

innatelearnedtaught

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AA larger base of support makes a performer more stable.

BA gymnast widens the feet on landing to avoid stepping.

CA lower centre of mass makes a performer more stable.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

Flexion means a decrease in the angle at a joint.

TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Biomechanical Principles and Levers, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Start revising, £5 a month See how the method works

Or £46 a year, about £3.83 a month. Cancel anytime.