Year 11 - Science
Changing momentum
Forces make things change
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores forces, interactions, and Newton's laws, including motion, rotation, and momentum. It covers reaction times, stopping distances, and deceleration dangers. Emphasis is on force diagrams, calculations, experiments, and evaluating methods for accuracy and safety.
Lesson Summary
You will learn to use the equation force = mass × change in velocity ÷ change in time to calculate the size of force involved in changing momentum in a certain amount of time.
Key Notes
- The momentum of an object is changed by a resultant force acting over a period of time.
- Force = rate of change of momentum, F = Δp ÷ t = (mv – mu) ÷ t
- The size of an impact force can be changed when the duration of the impact changes.
Vocabulary To Learn
- momentum: is the product of the mass and velocity of an object, p = m v, it is a vector quantity
- initial velocity, u: is the velocity of an object at the start of a phase of motion, represented by u
- final velocity, v: is the velocity of an object at the end of a phase of motion, represented by v
- rate of change of momentum: is the change in momentum per second, this is equal to the resultant force acting on an object
Common Mistakes To Avoid
- Pupils often confuse the terms force and momentum.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
The momentum of an object is changed by a resultant force acting over a period of time. Force = rate of change of momentum, F = Δp ÷ t = (mv – mu) ÷ t.
2. Define this scientific word and use it in context. 'momentum'
is the product of the mass and velocity of an object, p = m v, it is a vector quantity. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils often confuse the terms force and momentum. Correction: Make explicit the understanding that forces change the motion of an object, and that the motion of an object (that a force can change) can be described by its momentum.
More Lessons In This Unit
- Balancing Study Guide
- Conservation of momentum Study Guide
- Force, mass and acceleration (a = (v – u)/t) Study Guide
- Force, mass and acceleration (a = Δv/t) Study Guide
- Forces in two dimensions Study Guide
- Forces in two dimensions (including resolution of a force) Study Guide
- Moments, levers and gears Study Guide
- Newton's Second Law Study Guide
- Newton's Second Law (including inertia) Study Guide
- Newton's Third Law Study Guide
- Newton's Third Law (with free body diagrams in 2D) Study Guide
- Resultant forces and their effects Study Guide
- Stopping Study Guide
- Stopping (and estimating stopping distances) Study Guide
- Stopping safely Study Guide
- Terminal velocity Study Guide
- Terminal velocity (including graphical representation) Study Guide
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