8th Grade Forces and Motion

All objects in the universe are attracted to each other by the force of

• effort

• friction

• gravity

• inertia

A car travels south at a rate of 60 mph. Which term refers to both speed and direction?

• acceleration

• friction

• momentum

• velocity

What must happen to an object in order to accelerate it?

• An unbalanced net force must be applied.

• Some weight must be removed.

• Its frictional coefficient must be reduced.

• It must contain momentum.

Addy is learning how to roller blade and her mother does not want her to go too fast. On which kind of floor surface would Addy travel the slowest?

• carpet

• concrete

• tile

• wood

When riding in a car, which change demonstrates the GREATEST effect of inertia?

• The car makes a sudden stop.

• The car slows down gradually.

• The car changes into another lane.

• The car runs out of gas and rolls to a stop.

Michael is riding his bike. When he is coasting (riding without pedaling) his bike will come to a stop. Which will case Michael's bike to stop?

• an increase in kinetic energy

• Earth's magnetic field

• the property of inertia

• the force of friction

If you travel to a planet with half the mass of Earth what happens to your weight when you are on that planet?

• Your weight would stay the same.

• You would no longer have any weight.

• Your weight would increase by one-half.

• Your weight would decrease by one-half.

Which statement BEST explains how the car is moving?

• The car is slowing down.

• The car is speeding up.

• The car is accelerating at a constant rate.

• The car is decelerating at a constant rate.

What happens to an object if the forces acting upon it are unbalanced?

• its motion will not change

• the net force will be zero

• the object will come to a stop

• its motion will change

Dan runs 100 meters is 10 seconds. What is his average speed?

• 1m/s

• 10m/s

• 100m/s

• 1000m/s