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Wheels, Pulleys and Gears. 8.3. Wheels. Centre of a wheel is called the axle The outside the wheel is the rim A wheel is a special type of lever: Each spoke of the wheel is a lever The axle is the fulcrum Wheel rim is the outer end of the lever. http:// www.youtube.com/watch?v=HMNwEF4KDU0.
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Wheels • Centre of a wheel is called the axle • The outside the wheel is the rim • A wheel is a special type of lever: • Each spoke of the wheel is a lever • The axle is the fulcrum • Wheel rim is the outer end of the lever
http://www.youtube.com/watch?v=HMNwEF4KDU0 http://www.youtube.com/watch?v=QF7odK55gkI
Pulleys • A wheel with a groove. • Changes a downwards force into an upwards motion. • Using two pulleys halves the size of the effort force required providing a mechanical advantage of 2. • A number of pulleys in an arrangement called a Block and Tackle
Gears • Gears are wheels that have teeth around their rim. • A set of gears are called a Gear Train • The gear that supplies the force is the Driving Gear the gear connected is the Driven Gear • Different gears are chosen to either increase the force or the speed of turning http://www.youtube.com/watch?v=XZgsV0AZJJ0
Gear as a force multiplier • The driving gear is smaller than the driven gear • This is called gearing down
Gears as a speed Multiplier • The driving gear is smaller than the driven gear • This is called gearing down