| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.92 |
| Score | 0% | 58% |
What type of load creates different stresses at different locations on a structure?
non-uniformly distributed load |
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static uniformly distributed load |
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impact load |
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dynamic load |
A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.
Which of the following is the formula for torque?
τ = r/F |
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τ = rF |
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τ = F/r |
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τ = F/r2 |
Torque measures force applied during rotation: τ = rF. Torque (τ, the Greek letter tau) = the radius of the lever arm (r) multiplied by the force (F) applied. Radius is measured from the center of rotation or fulcrum to the point at which the perpendicular force is being applied. The resulting unit for torque is newton-meter (N-m) or foot-pound (ft-lb).
| 42.9 lbs. | |
| 21.4 lbs. | |
| 14.3 lbs. | |
| 44.9 lbs. |
This problem describes an inclined plane and, for an inclined plane, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance:
Fede = Frdr
Plugging in the variables from this problem yields:
Fe x 14 ft. = 200 lbs. x 3 ft.
Fe = \( \frac{600 ft⋅lb}{14 ft.} \) = 42.9 lbs.
What type of load varies with time or affects a structure that experiences a high degree of movement?
dynamic load |
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static load |
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concentrated load |
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impact load |
A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.
Which of the following represents how much two materials resist sliding across each other?
static friction |
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coefficient of friction |
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normal friction |
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kinetic friction |
Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.