Chapter 4 (x2) - Work, Power, and Simple Machines (MFE)

An example of work being done is

• a box being carried a distance

• a person pushing against a closed door that remains closed

• a person pushing a lawn mower and cutting the grass

• all of the above

Work divided by time equals

• force

• distance

• power

• mass

The work input of a crowbar is equal to the

• force applied to the handle

• distance the handle moves

• force applied to the handle times the distance the handle moves

• force applied by the resistance times the distance through which this force is applied

Machines

• multiply work

• multiply force or distance

• apply an effort force

• make work output greater than work input

Without friction there would be

• less machine efficiency

• greater work output than work input

• greater work input than work output

• equal work input and output

A ramp is a simple machine called the

• wedge

• inclined plane

• pulley

• lever

Sharpening a wedge

• decreases the mechanical advantage

• increases the effort force

• decreases the mechanical advantage and increases the effort force

• increases the mechanical advantage and decreases the effort force

For work to be done, the direction of

• motion must be perpendicular to the direction of the applied force

• the applied force must be opposite to the direction of motion

• the applied force must be perpendicular to the direction of motion

• the applied force must be the same as the direction of motion

Work is force times

• area

• distance

• weight

• mass

The amount of work done when a force of 300 N moves an object a distance of 2m is

• 600 N

• 600 N-m

• 150 N

• 150 N-m