| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.87 |
| Score | 0% | 57% |
What is work?
The movement of an object by a force |
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Force per unit time |
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Force per unit distance |
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The potential for exertion |
Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done. By definition, work is the displacement of an object resulting from applied force.
Which of the following is not a characteristic of a ceramic?
low corrosive action |
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high melting point |
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chemically stable |
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low density |
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?
Pascal's law |
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mechanical advantage |
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conservation of mechanical energy |
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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.
| 5 lbs. | |
| 10 lbs. | |
| 0 lbs. | |
| 30 lbs. |
To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:
Rada = Rbdb
where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.Solving for Ra, our missing value, and plugging in our variables yields:
Ra = \( \frac{R_bd_b}{d_a} \) = \( \frac{5 lbs. \times 6 ft.}{3 ft.} \) = \( \frac{30 ft⋅lb}{3 ft.} \) = 10 lbs.
The principle of conservation of mechanical energy states that, as long as no other forces are applied, what will remain constant as an object falls?
total mechanical energy |
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kinetic energy |
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potential energy |
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acceleration |
As an object falls, its potential energy is converted into kinetic energy. The principle of conservation of mechanical energy states that, as long as no other forces are applied, total mechanical energy (PE + KE) of the object will remain constant at all points in its descent.