| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.92 |
| Score | 0% | 58% |
Which of the following is not a type of structural load?
dead load |
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wind load |
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occupancy load |
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live load |
Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.
An object's resistance to changes in direction is known as:
inertia |
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mass |
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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.
Force of friction due to kinetic friction is __________ the force of friction due to static friction.
higher than |
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the same as |
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opposite |
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lower than |
The formula for force of friction (Ff) is the same whether kinetic or static friction applies: Ff = μFN. To distinguish between kinetic and static friction, μk and μs are often used in place of μ.
Lisa lifts a 25 pound box from the floor onto a loading dock 4 ft. off the ground. Sam slides the same box along a ramp to move it up another 4 ft. onto a flatbed truck. Who has done more work?
Neither have done any work |
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Lisa |
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Sam |
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They have done an equal amount of work |
Work is force multiplied by distance. Because both Connie and Sam moved the same weight the same distance they have done an equal amount of work. Sam employed the mechnacial advantage of an inclined plane so he exerted less effort to do the work but the amount of work done was still the same.
What is the first step to solving a problem where multiple forces are acting on an object?
calculate kinetic energy |
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calculate potential energy |
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calculate the net force |
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calculate the total force |
In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.