Physics Ka3

Question 1

What are forces measured in?

Answer 1

Newtons (N)

Question 2

What are examples of contact forces?

Answer 2

Friction, air resistance, reaction forces

Question 3

What are examples of non-contact forces?

Answer 3

Gravitational, magnetic

Question 4

What are non-contact forces?

Answer 4

Forces that have a region around them called a field where they affect objects

Question 5

What can electrostatic and magnetic fields do that gravitational fields can’t?

Answer 5

Repel as well as attract

Question 6

What is Newton’s first law?

Answer 6

If there are no forces acting on an object or the resultant force is zero: a stationary object stays still and a moving object will continue at the same speed and direction

Question 7

If the weight of a stationary plant pot is 5N and the support the table it is sitting on is also 5N, what is the resultant?

Answer 7

0

Question 8

Look at diagram (A) and label the forces acting on the submarine and state the vertical and horizontal resultants

Answer 8

Diagram A on sheet

Question 9

What is a free body force diagram? (FBF)

Answer 9

A diagram that only shows the forces acting on an object and ignores other objects

Question 10

Look at diagram B and label the different forces

Answer 10

B on sheet

Question 11

Look at diagram A and label the forces

Answer 11

A

Question 12

Look at diagram C and label forces

Answer 12

C

Question 13

Look at diagram D and label forces

Answer 13

D

Question 14

What is newtons 3rd law?

Answer 14

When 2 objects interact they exert equal and opposite forces on each other

Question 15

There are two people on skateboards holding a rope. If one person pulls what will happen?

Answer 15

The same force acts on both of them and they move together

Question 16

What happens when a boy falls from a tree?

Answer 16

The boy and the earth have the same force acting on them. The boy moves more than the earth because his mass it much smaller

Question 17

When a car is driving on the road what are the forces?

Answer 17

The force of the friction of the road on the tyre is in the forward direction.
The force of the friction of the tyre on the road is in the reverse direction.

Question 18

What happens to the forces on an object that are balanced?

Answer 18

They cancel each other out

Question 19

An unbalanced force acting in the same direction as the motion of the body will make it ______ ___

Answer 19

Speed up

Question 20

An unbalanced force in the _______ ______ to the motion of the body will make it slow down.

Answer 20

Opposite direction

Question 21

The _______ the size of the unbalanced force the faster the object will speed up or slow down

Answer 21

Greater

Question 22

The car is running at its maximum speed so there is no acceleration. Are the forces balanced?

Answer 22

Yes

Question 23

Explain the forces in swimming

Answer 23

The swimmer pushes against the water and the water pushes back.

Question 24

What is the resultant force?

Answer 24

The single force that can replace all of the forces acting on an object and have the same effect