Starter quiz
- Which kind of force pulls objects down towards Earth's surface?
- friction force
- magnetic force
- gravitational force ✓
- lift force
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- The force that acts when surfaces grip or rub against each other is called ______.
- 'friction' ✓
- Which is the correct name for the force that makes things float in water?
- gravity
- thrust
- upthrust ✓
- water resistance
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- What do forces do? Forces cause objects to ______ their speed, direction of motion or shape.
- 'change' ✓
- Which of these forces only acts when the two objects are touching?
- The force of one magnet attracting an iron nail.
- The force of one magnet repelling another magnet.
- The gravitational force of planet Earth on a ball thrown in the air.
- The force exerted by a foot kicking a football. ✓
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What is the best way of describing this force?- The force of the foot.
- The force of the ball.
- The force of the foot on the ball. ✓
- The force between the foot and the ball.
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Exit quiz
- Match the correct definitions to the keywords.
- Contact force⇔A force that only acts when objects are touching. ✓
- Non-contact force⇔A force that can act whether objects are touching or not. ✓
- Find the non-contact forces.
- magnetic force ✓
- tension
- weight ✓
- electrostatic force ✓
- friction
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- Match up each kind of force with its definition.
- Weight⇔The gravitational force from a star, planet or moon. ✓
- Upthrust⇔The upwards force from a liquid or gas. ✓
- Friction⇔The force of one surface rubbing/gripping another surface. ✓
- Tension⇔The force from a stretched rope. ✓
- Which is the best explanation for why gravitational forces are non-contact forces?
- Gravitational forces are the attraction of Earth.
- Gravitational forces work by magnetism.
- Gravitational forces only act when objects are touching Earth’s surface.
- Gravitational forces only act when objects are not touching Earth’s surface.
- Gravitational forces act whether objects are touching Earth’s surface or not. ✓
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Which force does not act on this boat? The boat is not moving.- gravitational force
- upthrust
- air resistance ✓
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Look at the picture. Which of the following forces does not act on the moving sled?- The pull force of the person on the rope. ✓
- The friction force of the ground on the sled.
- The tension force of the rope on the sled.
- The gravitational force of Earth on the sled.
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Contact forces only act when objects are touching.
- Non-contact forces can act with or without the objects touching.
- Friction is a contact force that slows or prevents movement.
- Drag is a contact force that pushes against objects moving through liquids or gases.
Common misconception
An object 'has' force that provides it some kind of agency, which is independent of other objects.
Describe forces as interactions between two objects using the structure 'the force of object A on object B'.
Keywords
Contact force - Contact forces only act when objects are touching.
Friction - Friction is the force of one surface gripping or rubbing on another.
Drag - Objects moving through liquids and gases experience drag, a force that acts against the object’s motion.
Non-contact force - Non-contact forces can act with or without objects touching.
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