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Science Starter Wednesday 4/25. Which pulley has a greater mechanical advantage, a fixed pulley or a moveable pulley?. Mechanical Advantage. Why do we study Simple Machines?.
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Science Starter Wednesday 4/25 • Which pulley has a greater mechanical advantage, a fixed pulley or a moveable pulley?
Why do we study Simple Machines? • In physics and engineering, mechanical advantage (MA) is the factor by which a machine multiplies the force put into it. • MA = output force ÷ input force
Force-Distance Trade-off • When a machine changes the size of the force, the distance through which the force is exerted must also change. • Force and distance can increase but not together. W = F x D • When one increases the other must decrease.
Diagrams of Pulleys Fixed pulley: A fixed pulley changes the direction of a force; however, it does not create a mechanical advantage. Mechanical Advantage = 1 Movable Pulley: The mechanical advantage of a moveable pulley is equal to the number of ropes that support the moveable pulley. Mechanical Advantage = 2
COMPOUND PULLEY(Block & Tackle) • The main disadvantage is it travels a very long distance.
MA of Pulleys • Interpret the diagrams to find the mechanical advantage of each pulley system. 1. MA= 2. MA= 3. MA=
MA of Inclined Planes MA = length / height 1. What is the height of the inclined plane? 2. What is the length of the inclined plane? 3. What is the mechanical advantage of the inclined plane? 4. How much effort force would be needed to push the dump truck up the mountain?
MA = output force ÷ input force • To pull a weed out of a garden, you can apply a force of 50 N to the shovel. The shovel applies a force of 600 N to the weed. • What is the mechanical advantage of the shovel?
MA = output force ÷ input force • To pry a nail out of a wall, you can apply a force of 50 N to the hammer. The hammer applies a force of 650 N to the nail. • What is the mechanical advantage of the hammer?
MA = output force ÷ input force • To lift a block on a movable pulley, you can apply a force of 50 N to a rope. The rope applies a force of 700 N to the block. • What is the mechanical advantage of the rope?
MA = output force ÷ input force • To lift a refrigerator, you can apply a force of 50 N to the wedge. The wedge applies a force of 550 N to the weed. • What is the mechanical advantage of the wedge?
MA = output force ÷ input force • To lift a bookshelf, you can apply a force of 50 N to a wedge. The wedge applies a force of 800 N to the bookshelf. • What is the mechanical advantage of the wedge?
MA = output force ÷ input force • To lift a bookshelf, you can apply a force of 50 N to a wedge. The wedge applies a force of 800 N to the bookshelf. • What is the mechanical advantage of the wedge?
MA = output force ÷ input force • To pry a wooden board off of a treehouse, you can apply a force of 50 N to a lever. The lever applies a force of 750 N to the weed. • What is the mechanical advantage of the lever?
MA = output force ÷ input force • To pull a tree out of a yard, you can apply a force of 50 N to the shovel. The shovel applies a force of 900 N to the weed. • What is the mechanical advantage of the shovel?
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