| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.28 |
| Score | 0% | 66% |
A shovel is an example of which class of lever?
second |
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first |
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third |
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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.
The mechanical advantage of a block and tackle is equal to which of the following?
the number of pulleys |
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the number of loads |
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the number of input forces |
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the number of connecting ropes |
Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement. So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.
Which of the following is not a modulus of elasticity?
stretch modulus |
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bulk modulus |
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stress modulus |
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shear modulus |
The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).
An object's resistance to changes in direction is known as:
weight |
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inertia |
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kinetic energy |
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mass |
The more mass a substance has the more force is required to move it or to change its direction. This resistance to changes in direction is known as inertia.
| 40% | |
| 2% | |
| 20% | |
| 60% |