Simple Machines and Efficiency

Which of the following would be a frictionless machine?

• ideal

• lever

• wheel and axle

• pulley

• wedge

In real simple machines, work input is work:

• done on the machine

• done by the machine

• that is 100% efficient

• that is over 100% efficient

In real simple machines, work output is work:

• done on the machine

• done by the machine

• that is 100% efficient

• that is over 100% efficient

Which of the following must be overcome in order for a simple machine to work?

• load, resistance, and weight.

• resistance, effort force, and weight

• weight, mechanical advantage, and efficiency

• load, mechanical advantage, and ideal machine

Mechanical advantage is the number of times a machine _____ the effort.

• multiplies

• reduces

• redirects

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A machine with a ratio greater than 1:

• multiplies the input force so the machine would be good to help move heavy objects.

• does not multiply the force, but increases distance and speed.

• is good for lifting and moving objects quicker.

• Is not good for lifting or moving objects quicker.

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The purpose of a simple machine is to reduce the amount of _____ needed to accomplish a task.

• force

• work

• mechanical advantage

• efficiency

Using an inclined plane to move a piano into a truck:

• does not reduce the amount of work, but does make the work easier by using less force to move the piano.

• does not reduce the amount of force, but does make the work easier to move the piano.

• does reduce the amount of work and makes the work easier by using less force to move the piano.

• increases the amount of work by using more force to move the piano.

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As you increase the length of an inclined plane, you would need ____ to move a piano.

• less force

• more force

• less work

• more work

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Which of the following would be a real machine and have friction?

• wheel and axle

• inclined plane

• lever

• pulley

• all are real machines which produce friciton