Physics - Force & Newton's Laws

p. 124, #1 (a): List 3 examples of a force causing an object to start moving.

p. 124, #1 (b): List 3 examples of a force causing an object to stop moving.

p. 124, #1 (c): List 3 examples of a force causing an object to change its direction of motion.

p. 124, #2. Give two examples of field forces described in this section and two examples of contact forces you observe in everyday life.

p. 124, #3. What is the SI unit of force?

• newtons

• meters

• meters/second

• kilograms

See chart on page 121.

N =

• kg*m/s²

• kg*m/s

• m/s²

• kg*m

p. 125: What is Newton's First Law?

The tendency of an object not to accelerate is called:

• inertia

• gravity

• friction

• retardation

p. 125: Newton's first law says that when the net external force on an object is zero, the object's _____________ is zero.

• acceleration

• velocity

• time

• length

p. 125: Why does a hovercraft float on a cushion of air above the water?

• Air provides less resistance to motion that water.

• Air provides more resistance to motion that water.

• Air is less flammable and thus safer than water.

• The air cushion protects underwater wildlife.