Work, Power & Simple Machines

Work is the product of?

• Speed and force

• Force and distance

• Power and force

• Motion and force

Which requirements are necessary in order for a force to do work on an object?

• The Speed and force must be the same

• The force and distance must be in the same direction

• Some of the force must act in the same direction as the object moves

• The Motion and force must act in the same direction as the object moves

Which of the following is a unit of power?

• joule

• watt

• horsepower

• newton

Generally speaking, how much work is done when a vertical force acts on an object moving horizontally?

• A high amount of work

• A moderate amount of work

• A low amount of work

• Zero work

Power is equal to work divided by

• time

• force

• distance

• mechanical advantage

How is the work output of a machine related to its work input?

• Always less

• Always greater

• Always equal

• Always zero

Why is the actual mechanical advantage of a machine always less than its ideal mechanical advantage?

• The presence of friction results in the actual mechanical advantage of a machine always being more than its ideal mechanical advantage.

• The presence of friction results in the actual mechanical advantage of a machine always being less than its ideal mechanical advantage

A machine with a 5-N input force and a 25-N output force has a mechanical advantage of?

• 2

• 5

• 20

• 125

The mechanical advantage of a pulley system depends upon?

• The diameter of the pulley wheels

• The length of the rope

• The number of sections of rope

• The direction of the input force

Tags

NGSS.MS-PS2-2

No machine can be 100% efficient because of

• Thermal energy

• Waste energy

• Convection energy

• Friction

Tags

NGSS.MS-PS2-5