Which of these statements about Newton's third law of motion is correct?
The forces are always contact forces
The forces act on the same object
The forces act on two different objects
Which of these is the best example of Newton’s third law in action?
A body accelerating when a resultant force is acting on it
Earth's gravity attracting a hot air balloon and the hot air balloon’s gravity attracting the Earth
A body travelling in a straight line until a resultant force acts on it
What is the unit of force?
Joule (J)
Watt (W)
Newton (N)
What are contact forces?
Forces between similar objects
Forces between touching objects
Forces between objects that do not touch
What is a non-contact force?
Forces between objects that are different from each other
Which of these is a contact force?
Friction
Attraction
Repulsion
Which of these involves a contact force?
A planet in orbit around a star
A skydiver falling through the air
Electrons attracted to the nucleus of an atom
Which of these is a non-contact force?
Normal contact force
Weight
What is the gravity force, or weight, of a 40 kg child on Earth?
40 kg
4.1 N
400 N
What must an object have in order to be affected by gravity?
Charge
Mass
Magnetism