GCSE Physics paper 2 missed questions

What is a force?

A push or pull on an object caused by it interacting with something

Give two effects that the gravity of a really big mass has on objects in its gravitational field

• It makes objects fall towards the mass

• Gives the objects a weight

What are four differences between weight and mass?

• Weight is a force, mass isn’t

• Weight is measured in newtons, mass in kilograms

• Weight is measured using a calibrated swing whereas mass is using a mass balance

• Weight depends on an object’s location, mass doesn’t

Define the centre of mass of an object

The point where an objects mass can be considered concentrated.

What is a resultant force?

A single force with the same effect as all forces acting on a single point

How do submarines use upthrust?

They fill tanks with water or air to make their weight more or less than the upthrust acting on them

Why does an object get hotter when pushed along a rough surface? [2]

Work is done against frictional forces and some is transferred to thermal energy stores.

Define displacement

How far an object moves in a given direction, measured in a straight line from starting point to finishing point

What are the typical speeds in m/s for the following: walking, running, cycling, car, train, plane

• 1.5m/s

• 3m/s

• 6m/s

• 25m/s

• 30m/s

• 250m/s

Define friction

A force between two objects, acting in opposite direction to movement.

Describe the two cases where you get friction

• Surface friction between two surfaces in contact

• Drag when an object moves in a fluid

Define terminal velocity

The maximum, constant velocity of an object falling in fluid.

Explain how an object reaches terminal velocity.

As it falls, it accelerates, increasing drag between fluid and the object, reducing acceleration. Once the drag = weight, it stops accelerating, reaching terminal velocity.

What is Newton’s third law?

When two objects interact, they exert equal and opposite forces on eachother

Why is adjusting ruler to be vertical important in spring extension practical?

Reduces error in measuring spring extension as at an angle, measured extensions would be shorter

What does it mean when extension is no longer directly proportional to weight on a spring?

It has been inelastically deformed as it exceeded its limit of proportionality

What is a strength and weakness of using a balloon with dots on it to represent an expanding universe?

Strength - as balloon expands, dots get further apart, representing galaxies getting further apart

Weakness - dots only on surface of balloon while galaxies are spread throughout the universe / limit to how far ballon can expand

What is the second calculation for magnification?

Magnification = image distance (Between image and lens) / object distance (Between object and lens)

What are the two wasys to show a magnetic field has been produced around around a wire?

Move a compass around wire, changing direction of needle shows magnetic field produced or sprinkle iron filings around it, shaking the surface their on will show the magnetic field

What is the main cause of inaccuracy when measuring a light ray’s refraction?

Width of light ray makes it difficult to judge its centre

Why do scientists publish experiment results when they can’t explain them? [2]

• Allow for peer review of data

• Assessing reproducibility of data

• To promote further experiments

• To encourage other scientists to develop theories

What is a systematic error?

An measuring error caused by equipment being consistently offset from true value.

What is a zero error?

When a measuring device gives a false reading when the true value of a quantity is zero

What is the difference between distance and displacement?

Distance is a scalar, displacement is a vector

How can an object accelerate without changing speed?

Changing direction changes velocity, acceleration is rate of change of velocity

Define breaking distance

Distance travelled under breaking force

Why does stopping distance increase when tired? [2]

Reaction time increases, increasing thinking distance, increasing stopping distance

Why is speed not directly proportional to stopping distance?

Although speed is directly proportional to thinking distance, it is not directly proportional to breaking distance

What are the two reasons why atmopsheric pressure decreases with altitude

Air molecules colliding with a surface create pressure

• Increasing altitude increases distance between air molecules, deccreasing number of collisions with a surface

• Increasing altitude decreases molecules above a surface, resulting in less weight of air than at lower altitudes

Describe the difference between a longitudinal and transverse wave

In a longitudinal wavem oscillations are parallel to direction of energy transfer whereas in transverser waves, oscillations are perpendicular to direction of energy transfer

Describe one piece of evidence showing when a sound wave travels through air, the wave and not the air travels.

When a speaker vibrates, air isn’t moved away to create a vacuum

Explain how a loudspeaker converts current in a circuit to a sound wave [6]

The varying current passes through a coil of wire, causing a varying force on the coil, making it and the cone vibrate, size of current affecting size of force. The vibrating cone moves air molecules, causing them to bunch together (compressions) and spread apart (rarefactions), creating pressure variations in air - a sound wave.

What are the three ways to increase strength of a motor?

• Increase current

• Use stronger magnets

• Add more turns to coil

What is the unit for magnetic flux density?

Tesla (T)

How do worn tyres increase breaking distance?

They have no tread left, meaning here unable to get rid of water on the road in wet conditions, increasing risk of skidding

What is a typical reaction time?

0.2-0.9s

What is the acceleration of an object in free fall?

9.8m/s^²

What is an emergency stop?

When maximum force is applied by breaks to stop a car in the shortest time possible

What are the dangers of large decelerations while driving? [2]

• Brakes could overheat - don’t work as well

• Higher risk of skidding

Which increase risk of accident

How do seatbelts work to keep the user safe?

They stretch slightly, increasing time taken for wearer to come to a stop during a crash

What are the types of EM waves from longest wavelength, lowest frequency to shortest wavelength, highest frequency

Radio waves, Micro waves, Infra-red, visible light, UV, X-rays, Gamma rays

(Raging Martians Invaded Venus Using X-ray Guns)

What is the amplitude of a wave?

Maximum displacement of a point on a wave from its undisturbed position

What is the wavelength of a wave?

Distance between the same point on two adjacent waves

What is the frequency of a wave?

Number of complete waves passing a certain point per second

What is the time period of a wave?

Time taken for a full cycle of a wave

What three things can happen when waves arrive at a boundary between two different materials?

Absorption, transmission and reflection

What is the difference between specular and diffuse reflection?

Specular - reflection in a single direction off a smooth surface

Diffuse - scattered reflection in different directions off a rough surface

What two properties of wave change as it is refracted?

wavelength and wave speed

What are the two ways an atom can produce EM waves?

1. Electrons rearranging themselves inside atoms

2. Changes in the nucleus of an atom (which produces gamma rays)

How does an alternating current and transmitter produce radio waves?

Alternating current causes electrons in transmitter to oscillate, generating radio waves

Why are long‑wave radio waves suitable for long‑distance communication? [3]

Due to their long wavelengths, they can diffract around the curved surface of the Earth and be received far away from the transmitterr

What are optical fibres? Why is visible light suitable to use in them?

• Thin glass or plastic fibres which carry data over long distances.

• Visible light isn’t easily absorbed or scattered as it travels along the fibre.

What is radiation dose?

A measure of risk of harm from radiation exposure, measured in millisieverts (mSv)

What two factors affect radiation dose?

• Total radiation absorbed

• How harmful type of radiation is