| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.71 |
| Score | 0% | 54% |
The principle of moments defines equilibrium in terms of:
power |
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energy |
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speed |
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torque |
According to the principle of moments, you can maintain equilibrium if the moments (forces) tending to clockwise rotation are equal to the moments tending to counterclockwise rotation. Another name for these moments of force is torque.
A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?
near the truck |
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tension is equal in all parts of the rope |
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near the car |
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in the middle |
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.
The mass of an object correlates to the size of the object but ultimately depends on:
gravity |
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the object's weight |
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the object's potential energy |
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the object's density |
Mass is a measure of the amount of matter in an object. In general, larger objects have larger mass than smaller objects but mass ultimately depends on how compact (dense) a substance is.
A wedge converts force applied to its blunt end into force __________ its inclined surface.
perpendicular to |
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opposite to |
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along |
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parallel to |
The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.
The mechanical advantage of a third class lever is always:
less than one |
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equal to one |
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not equal to one |
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greater than 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.