| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.81 |
| Score | 0% | 56% |
A shovel is an example of which class of lever?
a shovel is not a lever |
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second |
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third |
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first |
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.
Which of these will have the most impact on the kinetic energy of an object?
its weight |
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its mass |
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its direction |
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its speed |
Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.
Which of the following statements about drag is false?
slower objects experience more drag than faster objects |
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the amount of drag depends on the speed of an object |
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the amount of drag depends on the shape of an object |
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drag occurs during movement through a fluid |
Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.
Which of the following represents how much two materials resist sliding across each other?
static friction |
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coefficient of friction |
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kinetic friction |
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normal friction |
Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.
Which of the following will increase the mechanical advantage of this inclined plane?
lengthen the ramp |
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increase the force acting at the blue arrow |
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shorten the ramp |
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lower the force acting at the blue arrow |
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.