| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.46 |
| Score | 0% | 69% |
Power is the rate at which:
input force is transferred to output force |
|
friction is overcome |
|
work is done |
|
potential energy is converted into kinetic energy |
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.
The principle of moments defines equilibrium in terms of:
energy |
|
speed |
|
power |
|
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.
When all forces acting on a system cancel each other out, this is called:
potential energy |
|
rest |
|
equilibrium |
|
stasis |
When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments.
The mass of an object correlates to the size of the object but ultimately depends on:
the object's density |
|
gravity |
|
the object's potential energy |
|
the object's weight |
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.
An object's resistance to changes in direction is known as:
kinetic energy |
|
inertia |
|
weight |
|
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.