| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.27 |
| Score | 0% | 65% |
Which of these will have the most impact on the kinetic energy of an object?
its mass |
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its weight |
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its speed |
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its direction |
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.
A ramp is an example of which kind of simple machine?
first-class lever |
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none of these |
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wedge |
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inclined plane |
An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.
Hydraulics is the transmission of force through the use of which of the following?
torque |
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gear systems |
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air pressure |
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liquids |
Hydraulics is the transmission of force through the use of liquids. Liquids are especially suited for transferring force in complex machines because they compress very little and can occupy very small spaces. Hydraulic pressure is calculated by dividing force by the area over which it is applied: P = F/A where F is force in pounds, A is area in square inches, and the resulting pressure is in pounds per square inch (psi).
What is the first step to solving a problem where multiple forces are acting on an object?
calculate potential energy |
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calculate kinetic energy |
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calculate the total force |
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calculate the net force |
In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.
Specific gravity is a comparison of the density of an object with the density of:
oil |
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water |
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air |
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carbon |
Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer.