Ch 3, for Quiz 1

The best way to describe the rate of motion of an object that changes speed several times is to calculate the object’s ___.

• Average speed

• Constant speed

• instantaneous speed

• Variable speed

A body accelerates if it ___.

b. c. d.

• Speeds up

• Slows down

• changes direction

• All of these

___ acts between surfaces that are in contact.

• Inertia

• Friction

• gravity

• A net force

An object’s weight is directly related to its ___.

• Volume

• Velocity

• mass

• Shape

A constant velocity means acceleration is ___.

• Positive

• Negative

• increasing

• Zero

Any change over time is called a(n) ___.

• Rate

• Net force

• average

• Displacement

If Kim won a 300-m race in 40 s, her rate of speed was ___.

• 15 m/s

• 25 m/s

• 7.5 m/s

• 8.5 m/s

If you draw a time-distance graph and place units of seconds on the horizontal axis, you would place units of ___ o the vertical axis.

• Grams

• Meters

• newtons

• Kilograms

A person in a head-on collision, who is not wearing a seat belt, continues to move forward at the same speed of the car because of ___.

• Inertia

• Friction

• weight

• Gravity

Mass is measured in units called ___,

• Grams

• Newtons

• pounds

• Ounces