| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.62 |
| Score | 0% | 72% |
For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?
all of these are correct |
|
the portions of the system at an altitude below the input |
|
everywhere in the system |
|
the portions of the system at an altitude above the input |
Pascal's law states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. For a hydraulic system, this means that a pressure applied to the input of the system will increase the pressure everywhere in the system.
The force required to initally get an object moving is __________ the force required to keep it moving.
the same as |
|
higher than |
|
lower than |
|
opposite |
For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).
The mechanical advantage of a wheel and axle is equal to the:
difference in the diameters of the wheels |
|
ratio of the diameters of the wheels |
|
length of the axle |
|
difference in the lengths of the axles |
A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.
On Earth, acceleration due to gravity (g) is approximately __________.
9.8 m/s2 |
|
1 m/s |
|
6.67 x 10-11 m/s2 |
|
1 m/s2 |
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.
Friction resists movement in a direction __________ to the movement.
perpendicular |
|
opposite |
|
parallel |
|
normal |
Friction resists movement. Kinetic (also called sliding or dynamic) friction resists movement in a direction opposite to the movement. Because it opposes movement, kinetic friction will eventually bring an object to a stop. An example is a rock that's sliding across ice.