| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.32 |
| Score | 0% | 66% |
Tension is a force that does which of the following?
slows an object |
|
stretches an object |
|
heats up an object |
|
compacts an object |
Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.
Collinear forces:
act in a common plane |
|
pass through a common point |
|
are unrelated to each other |
|
act along the same line of action |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
| 6.67 lbs. | |
| 2.22 lbs. | |
| 3.33 lbs. | |
| 26.67 lbs. |
To balance this lever the torques on each side of the fulcrum must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:
Rada = Rbdb
where a represents the left side of the fulcrum and b the right, R is resistance (weight) and d is the distance from the fulcrum.Solving for Rb, our missing value, and plugging in our variables yields:
Rb = \( \frac{R_ad_a}{d_b} \) = \( \frac{40 lbs. \times 1 ft.}{6 ft.} \) = \( \frac{40 ft⋅lb}{6 ft.} \) = 6.67 lbs.
Which of the following is not a characteristic of a ceramic?
low corrosive action |
|
low density |
|
high melting point |
|
chemically stable |
Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.
The work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. This defines which of the following?
mechanical advantage |
|
conservation of mechanical energy |
|
Pascal's law |
|
work-energy theorem |
The work-energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. Simply put, work imparts kinetic energy to the matter upon which the work is being done.