Science Term 2 Exam- Physics

Question 0

Whats the difference between speed and velocity

Answer 0

Speed is how fast something is going

Velocity is how fast something is going in a certain direction. Negative and positive numbers are used

Question 1

How to: Distance time graphs

Answer 1

Horizontal axis (x axis) is for time
Vertical axis (y axis) is for distance
Your graph must have a title, labelled axis with units, the scale must be even
The gradient (slope) of the line tells us the speed of the object
If it has a positive gradient means it has a positive speed
If it has a negative gradient means it has a negative speed

Question 2

Units

Answer 2

1km = 1000 meters
1m = 100 cm
1cm = 10mm

Question 3

Distance, time and velocity

Answer 3

To find velocity/speed- d / t
To find distance- v x t
To find time- d / v

Question 4

What are ways to unit speed

Answer 4

Km/h Kmh-1 = m / s
M/s Ms-1 = k / h

Ms-1 to Kmh-1 = Ms-1 x 3.6
Kmh-1 to Ms-1= Kmh-1 / 3.6

Question 5

What is a force?

Answer 5

A force is a push or pull that can change an objects shape, size, and velocity

Question 6

What is the difference between contact forces and non contact forces?

Answer 6

Contact forces are when objects are touching and non contact forces are when there is no physical touching (eg gravity)

Question 7

How do you measure force

Answer 7

Units for force is Newton (N)

1N is the amount of force needed to accelerate 1kg at 1ms-2 (Units for acceleration is ms-2 or m/s/s)

Question 8

Types of forces

Answer 8

Gravity
Air resistance
Support
Uplift
Friction 
Thrust
Buoyancy

Question 9

Force diagrams

Answer 9

We use arrows to represent forces
Sometimes the size of the arrow represents the size of the force
Sometimes the forces are too different and we just write the value
If forces are in the same direction you add the amounts to get the net force
But if they are in opposite directions you subtract

Question 10

Newtons first law of motion

Answer 10

An object that is at rest will stay at rest unless acted on by a outside force
An object in motion will stay in motion

Question 11

Balanced and unbalanced forces

Answer 11

When forces are balanced we can say they are equilibrium
When they are unbalanced they have a net force
Balanced eg. 2N to the left and 2N to the right
Unbalanced eg. 4N to the left and 1N to the right

Question 12

What is a net force?

Answer 12

The sum of all the forces is a Net Force

Question 13

Newtons 3rd Law

Answer 13

For every force there is a equal opposite reaction of force

Eg. Standing on the ground, balance game, stepping off a boat, kicking a ball

Question 14

Non contact forces

Answer 14

Gravity
Magnetism
Electricity

Question 15

What is gravity?

Answer 15

Gravity is the attraction between 2 masses
The closer the masses the greater the attraction
The further apart the masses the weaker the attraction
The larger the mass the greater the attraction
The smaller the mass the smaller the attraction

Question 16

Mass V Weight

Answer 16

Mass is the amount of matter/stuff/quantity of material that makes you, it doesnt change
Weight is the gravitational pull on your mass

W= mass x force of gravity = mg
Measured in Newtons

Eg. w= 75 x 10 = 75N

Question 17

Weightless in space

Answer 17

The person and the space craft are falling at the same rate and since they are falling at the same rate there is no observational reaction force

Question 18

Acceleration

Answer 18

Acceleration is a change in motion (velocity) of a object
Forces cause acceleration
It is measured in metres per second per second
Acceleration= (Final speed - Initial speed) / time
A= Vf - Vi / T
A triangle means a change in

Question 19

Working out acceleration time and velocity

Answer 19

A= Change in velocity / Time
T= Change in velocity / Acceleration
Change in velocity= Acceleration x Time