| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.52 |
| Score | 0% | 70% |
| 420 ft. | |
| 0 ft. | |
| 5 ft. | |
| 42 ft. |
Win = Wout
Feffort x deffort = Fresistance x dresistance
In this problem, the effort work is 1050 ft⋅lb and the resistance force is 210 lbs. and we need to calculate the resistance distance:
Win = Fresistance x dresistance
1050 ft⋅lb = 210 lbs. x dresistance
dresistance = \( \frac{1050ft⋅lb}{210 lbs.} \) = 5 ft.
What defines the mechanical advantage of a first class lever?
position of the fulcrum |
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output force |
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output distance |
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input force |
A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.
Which of the following will increase the mechanical advantage of this inclined plane?
increase the force acting at the blue arrow |
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shorten the ramp |
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lengthen 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.
A watt is the unit for which of the following?
power |
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work |
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energy |
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mechanical advantage |
Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.
On Earth, acceleration due to gravity (g) is approximately __________.
9.8 m/s2 |
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6.67 x 10-11 m/s2 |
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1 m/s2 |
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1 m/s |
Newton's Law of Univeral Gravitation defines the general formula for the attraction of gravity between two objects: \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) . In the specific case of an object falling toward Earth, the acceleration due to gravity (g) is approximately 9.8 m/s2.