7K - Forces

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.

What is used to measure forces?

• a force meter with a spring inside
• a force meter with string inside
• a ruler
• a clamp and stand

An elastic material:

• does not stretch.
• stretches and stays in its new shape.
• stretches and then goes back to its original shape.
• cannot be squashed.

What is the extension of a spring?

• The stretched length of the spring.
• The length of a compressed spring.
• The stretched length minus the original length.
• The length of the spring before it has been stretched.

At which point on this graph does the extension stop being proportional to the force?

• A

• B

• C

• D

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