Forces & resultant force.

What can forces do?

• make things start or stop moving
• change the shape of things
• make moving things change direction
• all of the above

Which answer shows three non-contact forces?

• magnetism, gravity, friction
• gravity, friction, upthrust
• gravity, static electricity, magnetism
• upthrust, static electricity, friction

What are the units used for measuring forces?

• metres
• newtons
• kilograms
• grams

Which is true?

• Your weight would be the same on the Earth and on the Moon.
• Your mass would be the same on the Earth and on the Moon.
• Your weight would be more on the Moon than on the Earth.
• Your mass would be less on the Moon than on the Earth.

Which of the following sentences about friction is not correct?

• Friction can make an object get hotter.
• Friction wears car tyres away.
• Friction slows down a ball rolling in grass.
• Friction can speed up a falling object.

Which of these would produce the most friction when they rub together?

• a rough surface and a smooth one
• two smooth surfaces
• two rough surfaces
• two smooth surfaces with oil between them

Which of these things will not happen if there are unbalanced forces on an object?

• It will start to move.
• It will slow down.
• It will continue to move at the same speed.
• It will change direction.

A car needs a force from its engine to keep moving because:

• everything needs a force to keep moving.
• gravity is acting to slow it down.
• it needs a force to balance friction and air resistance.
• weight balances friction.

How do you know it is the biggest force?

• The arrow is smaller

• The arrow is bigger

• The girl is pulling in that direction

What does a vector (arrow) tell us about the force? (2 correct answers)

• How smelly it is

• The direction it is

• How strong it is

• What the force is