Reviewing forces.

What is a simple way to describe a force?

• A push or a pull.

• The result of a big impact.

• A state of mind.

• An ancient power based on interactions between living things.

Gravity is a force of attraction that

• Only acts on small masses.

• Only acts on large masses.

• Acts evenly between two masses.

• Doesn't exist. The universal ether exerts a push on us to keep us floating off the planet.

What is the unit for force?

When we total all forces acting on an object we call it

• Net Force

• Resultant Force

• Normal Force

• Total Force

• Fred

When a person stands on a set of scales, they are measuring

• their length.

• their time.

• their weight.

• their mass.

• How annoying something is.

Answer explanation

The scales display mass. You need gravity to have weight and the scales are calibrated to do this. If you used Earth scales on Mars your mass would be given as too low. If you used them on Jupiter, you'd be given a very high mass.

Draw two forces represented by arrows on the car.

When the net or resultant force on an object is 0N, how would the object be moving.

• It wouldn't be.

• Very slowly but always changing.

• At a constant, unchanging speed.

• Very fast like greased lightning.

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A car's engine is providing 800N of forward force, the driver slams on the brakes which have a force of 1400N. What is the resultant or net force?

• 600N in the direction of motion
• 600N against the direction of motion
• 2200N in the direction of motion
• 2200N against the direction of motion

Friction is a resistance force. Can it ever move an object in a positive direction?

• Yes, when the object is being pushed or pulled
• No, friction always opposes motion
• Yes, but only in the absence of gravity
• No, friction only acts in a negative direction

Tension is

• A force that pulls

• A force that pushes

• No force, just a pull

• No force, just a push.

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