Chapter 4 (Forces)

Question 1

What are the effects of forces

Answer 1

-a body at rest moves
-a moving body increases in speed
-a moving body decreases in speed
-causes a moving object to change direction

Question 2

What are the newton laws

Answer 2

1: if all the forces acting on an object is balanced, it will experience no change in velocity
2: if all the forces acting on an object is unbalanced, it will experience a change in velocity
3: Forces occur in pairs, each pair is made up of an action and reaction force

Question 3

What is inertia

Answer 3

The inertia of an object refers to the reluctance of the object to change its state of rest or motion due to its mass

Question 4

What is friction

Answer 4

Friction is the contact force that opposes or tends to oppose motion between surfaces in contact

Question 5

What are the positive and negative effects of friction

Answer 5

positive
-we can walk without slipping
-moving objects are able to slow down when needed
negative
-cars are less efficient by up to 20%
-moving parts in machines, engines and motors suffer wear and tear

Question 6

How to reduce effects of friction

Answer 6

-using wheels
-using ball bearings
-using lubricants and polished surfaces
-using air cushion

Question 7

How to enhance effects of friction

Answer 7

-Using threads
-Using parachute
-Using chalk

Question 8

When does an object experience terminal velocity

Answer 8

When the air resistance acting on an object is equal to its weight. This means it has zero acceleration