Year 11 - Science
Resultant forces and their effects
Forces make things change
Study Hub
Study Guides
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 determine the change of motion caused by one dimensional forces acting on an object.
Key Notes
- A single resultant force has the same effect as several forces acting on an object
- If there is no resultant force on an object, it remains still or continues to move at a steady speed in a straight line
- If there is a resultant force on an object, it will accelerate in the direction of the force
- A resultant force acting in the opposite direction to movement will decelerate (slow down) an object
Vocabulary To Learn
- resultant force: the effect of a set of forces on an object
- Newton's First Law of motion: an object will remain at rest, or in motion in a straight line at constant speed, unless there is a resultant force acting on it
- velocity: the rate of change of displacement of an object, measured in metres per second (m/s)
- accelerate: a change in the speed and/or direction of an object
- decelerate: a decrease in the speed of an object
Common Mistakes To Avoid
- A common belief is that a resultant force is needed to keep an object in motion, and if no resultant force acts on an object then it must be stationary.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
A single resultant force has the same effect as several forces acting on an object. If there is no resultant force on an object, it remains still or continues to move at a steady speed in a straight line.
2. Define this scientific word and use it in context. 'resultant force'
the effect of a set of forces on an object. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: A common belief is that a resultant force is needed to keep an object in motion, and if no resultant force acts on an object then it must be stationary. Correction: Discuss examples in which friction is very low or absent, such as a puck sliding across an ice rink or an object being dropped during a space walk and extrapolate to what would happen if friction disappeared entirely.
More Lessons In This Unit
- Balancing Study Guide
- Changing momentum 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
- 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
Browse all guides in the Year 11 Science guide library.