Checkpoint Science 8.2 Forces and Motion

A car was moving along a straight road and suddenly came to a complete stop.

What is the primary force responsible for bringing the car to rest?

• Air resistance pushing against the car

• Centripetal force acting in the opposite direction

• Friction between the tires and the road

• Gravity pulling the car downward

An object has balanced forces acting on it. Which of these describes the movement of the object?

1. The object could be moving at a constant speed in a straight line.

2. The object could be moving at a constant speed in a circle.

3. The object could be stationary.

4. The object could be getting faster in a straight line.

• 3 and 4

• 1 and 2

• 2 and 4

• 1 and 3

The diagram shows the forces on an aeroplane in the air.

• thrust

• weight

• lift

• drag

If a sealed bottle containing air particles is heated, what happens to the pressure inside the bottle?

• it decreases

• it first decrease and then increases

• it increases

• it stays the same

What is the equation that links force, moment and distance?

• distance = moment / force

• distance = moment x force

• force = moment x distance

• moment = force / distance

How does air exert a pressure?

• The bottle particles are colliding each other

• The bottle is vibrating itself

• Gas particles are colliding with the bottle

• Gas particles are vibrating itself

Diagram shows distance/time graph for four travellers, A, B, C and D. In what time the speed of traveller B is 0 cm/minute?

• from 0.5 to 3 minutes

• from 1 to 2.5 minutes

• from 0 to 0.5 minutes

• from 3 to 4 minutes

A toy car travels a distance of 25 meters in 5 minutes.

What is the average speed of this toy car?

• 125 m/min

• 5 m/min

• 30 m/min

• 25 m/min

A fish is in water. The water exerts pressure on the fish.

Which of this causes pressure on the fish?

• The weight of water below the fish

• The weight of water beside the fish

• The weight of water all around the fish

• The weight of water above the fish

Which snail wins the race?

• A

• B

• C

• D