physical science ch. 6

Using a rope and pulley, Thomas applies a 3-newton force to lift an 18-newton weight 2 meters. If the efficiency of the pulley system is 75%, over what distance must Thomas apply the force?

• 12 meters

• 2 meters

• 16 meters

• 36 meters

The ability to cause change best describes:

• efficiency

• energy

• work

• power

When a 15-newton force is applied to one end of a lever 100 centimeters long, a 60-newton weight attached to the opposite end is lifted. What is the length of the input arm?

• 20 cm

• 40 cm

• 60 cm

• 80 cm

Units of energy include all of the following EXCEPT:

• BTU

• kilowatt-hour

• calorie

• watt

An input gear with 40 teeth is turns a smaller output gear with 8 teeth. What is the gear ratio of this system?

• 5

• 48

• 1/5

• 32

The term best described by the phrase, “a group of objects, effects, and variables that are related,” is:

• system

• mass

• energy

• efficiency

When a 50-newton force is applied to a rope and pulley, a 200-newton weight is lifted. What is the

mechanical advantage of the rope and pulley system?

• 0.25

• 150

• 250

• 4

As an object is raised to a higher position, the object is most likely to experience an increase in its:

• kinetic energy

• heat energy

• light energy

• potential energy

Claire uses a simple machine to lift a 5-newton mass 4 meters. What is the efficiency of the machine if Claire

does 25 joules of work?

• 125%

• 80%

• 20%

• 100%

A scientist is studying the growth-rate of oak trees in a forest. All of the following are part of the forest

system she studies EXCEPT the:

• age of the trees

• phase of the moon.

• amount of rainfall in the area..

• oil in which the oak trees are growing.