| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.69 |
| Score | 0% | 54% |
Which class of lever is used to increase force on an object in the same direction as the force is applied?
first |
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third |
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second |
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all of these |
A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.
Which of the following will increase the mechanical advantage of a second-class lever?
move the fulcrum between the force and the object being lifted |
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decrease the length of the lever |
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move the object being lifted farther away from the fulcrum |
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move the object being lifted closer to the fulcrum |
A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.
Concurrent forces:
act along the same line of action |
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act in a common dimension |
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act in a common plane |
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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.
Which of the following statements about drag is false?
the amount of drag depends on the speed of an object |
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slower objects experience more drag than faster objects |
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drag occurs during movement through a fluid |
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the amount of drag depends on the shape of an object |
Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.
Which of the following statements about this pulley configuration is false?
Changes the direction of and multiplies the effort force |
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This is a block and tackle pulley configuration |
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Mechanical advantage is the number of ropes that support the resistance |
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Only multiplies the effort force |
A block and tackle is a combination of one or more fixed pulleys and one or more movable pulleys where the fixed pulleys change the direction of the effort force and the movable pulleys multiply it. The mechanical advantage is equal to the number of times the effort force changes direction and can be increased by adding more pulley wheels to the system. An easy way to find the mechanical advantage of a block and tackle pulley system is to count the number of ropes that support the resistance.