| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.39 |
| Score | 0% | 68% |
Collinear forces:
act along the same line of action |
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act in a common plane |
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are unrelated to each other |
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pass through a common point |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
An object's resistance to changes in direction is known as:
mass |
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inertia |
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weight |
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kinetic energy |
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.
| 30 ft. | |
| 3 ft. | |
| 6 ft. | |
| 9 ft. |
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 db, our missing value, and plugging in our variables yields:
db = \( \frac{R_ad_a}{R_b} \) = \( \frac{10 lbs. \times 3 ft.}{10 lbs.} \) = \( \frac{30 ft⋅lb}{10 lbs.} \) = 3 ft.
Normal force is generally equal to the __________ of an object.
density |
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weight |
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coefficient of friction |
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mass |
Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight.
Which of the following is not a characteristic of a ceramic?
low density |
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high melting point |
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chemically stable |
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low corrosive action |
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.