Grade 8 Forces

Why does a parachutist need to open parachute before reaching the ground?

• Increase air resistance, so it will fall slower

• Decrease air resistance, so it will fall slower

• Increase air resistance, so it will fall faster

• Decrease air resistance, so it will fall faster

Which one is contact force?

• friction

• gravitational force

• electrostatic force

• magnetic force

Why outsole of shoes is designed like this?

• to increase friction

• to decrease friction

• to move easily in slippery floor

• to decrease weight

What is the name of force to make this object float on the water?

• bouyancy

• weight

• friction

• tension

The arrows represent forces. Which diagram will make the yellow team wins?

• 
• 
• 

Tension is categorized as a ...

• contact force

• non-contact force

This diagram shows an example of ....

• turning effect of forces

• forces can change direction

• forces can change motion

• forces can change shape

In this picture, the car will ...

• move with constant speed

• speed up

• slow down

• stop

This diagram shows an example of ....

• turning effect of forces

• forces can change direction

• forces can change motion

• forces can change size

A boy try to open a door by pulling the door in position A, B and C. Which statement is correct?

• Turning effect of force in A is greater than in B

• Turning effect of force in B is greater than in C

• Turning effect of force in A is the greatest

• Turning effect of force in C is the greatest