ICP review Test Ch 4

When a machine does work on an object the output work is

• always less than the input work

• always equal to the input work

• always greater than the input work

• sometimes equal to the input work

Approximately how much work do you do when you lift your 10 kg sister to a height of 1.5 m?

• 150 J

• 15 J

• 15 N

• 15 W

If the input force on a lever is 200 N, then the output force from that lever is 50N. What is the mechanical advantage of the lever?

• 1.0

• 4.0

• 6.0

• 0.25

A lever is 90% efficient. If 50 J of work are done on the lever, then how much work does the lever do on its load?

• 40 J

• 60 J

• 45 J

• 90 J

The efficiency of a pulley system is

• exactly 100%

• exactly 400%

• greater than 100%

• less than 100%

A machine can do any of the following, except

• increase work

• increase distance

• increase force

• change direction

Which sequence describes the energy conversions in a cars engine?

• chemical to thermal to mechanical

• mechanical to thermal to chemical

• thermal to mechanical to chemical

• kinetic to potential to mechanical

The kinetic energy from an objects motion always changes when which factor changes?

• the object's chemical potential energy

• the object's volume

• the object's direction of motion

• the object's speed

The __________ is the SI unit of energy.

What factor does NOT determine how much gravitational potential energy is in an object-Earth system?

• speed of the object

• mass of the object

• shape of the object

• volume of the object