Your Results | Global Average | |
---|---|---|
Questions | 5 | 5 |
Correct | 0 | 2.95 |
Score | 0% | 59% |
A shovel is an example of which class of lever?
second |
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third |
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first |
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a shovel is not a lever |
A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.
A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?
in the middle |
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near the truck |
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tension is equal in all parts of the rope |
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near the car |
Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.
Collinear forces:
act in a common plane |
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are unrelated to each other |
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act along the same line of action |
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pass through a common point |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
Which of the following represents the force a surface exerts when an object presses against it?
counter force |
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mass |
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normal force |
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friction |
Normal force (FN) represents the force a surface exerts when an object presses against it.
A fixed pulley has a mechanical advantage of:
-1 |
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0 |
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2 |
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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.