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Why is friction vital in helping us to move?
Starter: How do these objects use the idea of friction to do their job? Get some sand paper and wood
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End of Term Exam B5 exam – Wed 12th Feb That week Monday – finish physics Tuesday – revise B5 Wed – Exam Thurs – go over exam Week back – p4 exam (sorry)
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What do McFly know? Dougie: Friction is an energy that slows things down. Tom: Friction is caused by pressure between 2 things. Harry: Friction is a type of force which usually prevents sliding.
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Learning outcomes revise that friction is a force that acts in a direction to prevent (or tend to prevent) sliding motion explain how an interaction pair of forces enables a wheel to make a vehicle move explain how friction is caused by the irregularities of surfaces explain how the friction force balances the applied force up to a limit (for any given situation) Why is friction vital in helping us to move?
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Starting to Walk How does friction help us walk?
revise that friction is a force that acts in a direction to prevent (or tend to prevent) sliding motion
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One foot pushes back on the ground. What do you know about forces??! .
force exerted by foot on ground One foot pushes back on the ground. What do you know about forces??! . revise that friction is a force that acts in a direction to prevent (or tend to prevent) sliding motion
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force exerted by foot on ground force exerted by ground on foot The ground pushes back – an interaction pair of forces. It is the forward force, on your foot, that enables you to move forward. revise that friction is a force that acts in a direction to prevent (or tend to prevent) sliding motion
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How do the wheels on our car enable us to move?
Watch these clips and work out how the wheels enable our cars to move forwards. car driving off/mud/ice explain how an interaction pair of forces enables a wheel to make a vehicle move
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If the tyre grips the road and does not spin, the second force of the interaction pair results in a large forward force on the axle. This pushes the car forward.
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Other uses of Friction Think – Pair – Share :
What possible uses does friction have? Why is friction vital in helping us to move?
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From Stationary ….. Will the box move?
Jeff pushes the box with a force of 25 N, to try to slide it along. It does not move. The friction force exerted by the floor on the box is 25 N. This exactly balances Jeff’s push. Why is friction vital in helping us to move?
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From Stationary ….. Will the box move?
Jeff then pushes harder, with a force of 50 N. The box still does not move. The friction force exerted by the floor on the box is now 50 N. again, this balances Jeff’s push.
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From Stationary ….. Will the box move?
Jeff pushes harder still, exerting a force of 70 N. The box starts to move. 70 N is bigger than the maximum friction force for this box and floor surface. Why is friction vital in helping us to move?
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What causes friction. Make a list of surfaces that offer lots of friction, and those that only offer some. What are the key similarities between them?
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Think – Pair – Share How does friction work?
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Task Sketch a “zoomed in” view of a surface with good friction and explain how the surface causes the friction.
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Task Complete the friction learning mat.
Why is friction vital in helping us to move?
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Jelly & Chopstick Experiment
Soap experiment
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Complete Find Someone Who
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