AQA GCSE Combined Science Trilogy Physics Paper 2

What is a scalar quantity?

A quantity that has only magnitude

What is a vector quantity?

A quantity with magnitude and direction

How are vector quantities often represented?

• represented as a arrow

• length = magnitude

• direction = direction of vector quantity

What is a force?

A push or pull that acts on an object due to interaction with another object

What is a contact force?

When the objects are physically touching

What is a non-contact force?

When objects do not need to be touching for a force to act

Give some examples of contact forces

friction, air resistance, tension and normal contact force

Give some examples of non-contact forces

gravitational force, electrostatic force and magnetic force

What type of quantity is force?

vector

What is weight?

the force acting on an object due to gravity

What is gravity on an object caused by?

the gravitational field around the Earth

What does weight depend on?

the gravitational field strength at the point where the object is

What does 'centre of mass' refer to?

Where the weight of an object acts at a single point

What is weight proportional to?

mass

What is used to measure weight?

Newtonmeter

What is the unit of weight?

N (newtons)

What is a resultant force?

the overall force acting on an object

What is displacement?

the change in position of an object (distance)

What is the unit of work done?

Joules (J)

What is 1 joule equivalent to?

1 newton-metre

What does work done against frictional forces cause?

A rise in temperature

What forces cause stretching?

Pulling forces

What forces cause bending?

Push or Pull forces

What forces cause compression?

Pushing forces

Why is more than one force needed to change the shape of a stationary object?

The second force is required to stop the object from moving

What is elastic deformation?

When the force is removed the deformation is reversed (object returns to its original shape)

What is inelastic deformation?

When the force is removed the deformation is not fully reversed (like an over-stretched spring)

What is extension proportional to?

The force applied (provided the limit of proportionality is not exceeded)

What is the unit of spring constant?

Newton per metre (N/m)

What type of quantity is distance?

scalar

What type of quantity is displacement?

vector

What type of quantity is speed?

scalar

What is typical walking speed?

1.5 m/s

What is typical running speed?

3 m/s

What is typing cycling speed?

6 m/s

What is typical car speed?

13-30 m/s

What is typical train speed?

50 m/s

What is typical aeroplane speed?

250 m/s

What is the typical speed of sound in air?

330 m/s

What type of quantity is velocity?

vector

Explain why someone moving in a circle is going at constant speed but not constant velocity

Velocity is both magnitude and direction.

Their direction is constantly changing, therefore their velocity is not constant

How can speed be calculated on a distance-time graph?

The gradient

What is the unit of acceleration?

m/s2

How can acceleration be calculated on a velocity-time graph?

The gradient

How can distance travelled be calculated on a velocity-time graph?

The area under the graph

What is the acceleration of an object falling freely due to gravity?

9.8 m/s2

What happens to an object falling through fluid?

• initially accelerates due to the force of gravity

• eventually the resultant force will be zero and the object will move at its terminal velocity

What is Newton's first law?

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force

What is inertia?

The tendency of an object to resist a change in motion

What is Newton's second law?

The acceleration of an object is proportional to the resultant force acting on the object, and inversely proportional to the mass of the object

What is inertial mass?

A measure of how difficult it is to change the velocity of an object, the ratio of force over acceleration

What symbol indicates approximation?

~

What is Newton's third law?

Whenever two objects interact, the forces they exert on each other are equal and opposite

How do you calculate stopping distance?

Stopping distance = thinking distance + braking distance

What is the typical range of a person's reaction time?

0.2 s to 0.9 s

What factors can affect a driver's reaction time?

Tiredness, drugs, alcohol, distractions

What factors can affect breaking distance?

• road/ weather conditions (ice or wet)

• condition of the vehicle (breaks and tyres)

Why does the temperature of the breaks increase when pressed?

• a force is applied to the brakes of a vehicle

• work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle

What may large decelerations lead to?

brakes overheating and/or loss of control

What is the unit of momentum?

kg m/s

What is the conservation of momentum?

In a closed system, the total momentum before an event is the same as after the event

Give an example of a transverse wave

Water ripples or any electromagnetic wave

Give an example of a longitudinal wave

sound waves

What is the difference between transverse and longitudinal waves? (Exact words)

Transverse waves: the oscillations are perpendicular to the direction of energy transfer

Longitudinal waves: the oscillations are parallel to the direction of energy transfer

What are the two features of a longitudinal wave?

compression and rarefaction

What is the amplitude?

Height of a wave (from the mid-line)

What is the wavelength?

distance between crests (peaks)

What is the frequency of a wave?

The number of complete waves passing a certain point per second

How do you calculate wave period?

What is the unit of frequency?

Hertz (Hz)

What is wave speed?

the speed at which the energy is transferred (or the wave moves) through the medium

What are electromagnetic waves?

Transverse waves that transfer energy from the source of the waves to an absorber

When do all electromagnetic waves travel at the same velocity?

In a vacuum or air

Name all the electromagnetic waves

Radio, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays

Which wave has the longest wavelength?

radio waves

Which wave length has the highest frequency?

gamma rays

Which wave can human eyes detect?

visible light

What causes refraction?

Refraction occurs because waves travel at different speeds in different mediums (like going from air to water)

How can radio waves be produced?

Oscillations in electrical circuits

How do radios in a car work?

When radio waves are absorbed they may create an alternating current with the same frequency as the radio wave itself, so radio waves can themselves induce oscillations in an electrical circuit

What can changes in atoms/ nuclei cause?

Generates electromagnetic waves (like gamma rays)

Which waves can cause health problems?

Ultraviolet waves, X-rays and gamma rays

What is a radiation dose?

a measure of the risk of harm resulting from an exposure of the body to the radiation

What can UV rays cause?

• skin to age prematurely

• increase the risk of skin cancer

What can X-rays and gamma rays cause?

cause the mutation of genes and cancer

What are radio waves used for?

television and radio

What are microwaves used for?

satellite communication and cooking food

What is infrared used for?

electrical heaters, cooking food, infrared cameras

What is visible light used for?

fibre optic communications

What is ultraviolet used for?

energy efficient lamps, sun tanning

What are X-rays and gamma rays used for?

Medical imaging and treatments

What happens when two magnets are brought close together?

they exert a force on each other