Your Results | Global Average | |
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Questions | 5 | 5 |
Correct | 0 | 3.06 |
Score | 0% | 61% |
A ramp is an example of which kind of simple machine?
wedge |
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inclined plane |
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none of these |
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first-class lever |
An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.
Which of the following will increase the mechanical advantage of this inclined plane?
shorten the ramp |
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increase the force acting at the blue arrow |
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lower the force acting at the blue arrow |
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lengthen the ramp |
The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In order to increase mechanical advantage, this ratio must increase which means making the effort distance longer and this can be accomplished by lengthening the length of the ramp.
The measure of how much of the power put into a machine is turned into movement or force is called:
mechanical advantage |
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force multiplication |
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efficiency |
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power |
The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output.
The mechanical advantage of a third class lever is always:
equal to one |
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less than one |
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greater than one |
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not equal to one |
A third class lever is designed to multiply distance and speed at the expense of effort force. Because the effort force is greater than the resistance, the mechanical advantage of a third class lever is always less than one.
An example of a third class lever is a broom. The fulcrum is at your hand on the end of the broom, the effort force is your other hand in the middle, and the resistance is at the bottom bristles. The effort force of your hand in the middle multiplies the distance and speed of the bristles at the bottom but at the expense of producing a brushing force that's less than the force you're applying with your hand.
A fixed pulley has a mechanical advantage of:
2 |
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0 |
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1 |
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-1 |
A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.