AQA GCSE Physics - Paper 2
What are vectors? - ANS- Quantities that have a magnitude and a direction
What are scalars? - ANS- Quantities that only have a magnitude
Examples of vectors - ANS- Force
Velocity
Displacement
Acceleration
Momentum
Examples of scalars - ANS- Speed
Distance
Mass
Temperature
Time
What are contact forces? - ANS- Forces that act when two objects are touching
What are non-contact forces? - ANS- Forces that act without the need for two objects to
be touching
Examples of contact forces - ANS- Friction
Air resistance
Tension in ropes
Normal contact force
Examples of non-contact forces - ANS- Magnetic force
Gravitational force
Electrostatic force
What is mass? - ANS- The amount of material an object is made of
It is the same value everywhere
Measured using a mass balance
What is weight? - ANS- The force acting on an object due to gravity
It depends on the strength of the gravitational field at the location of the object
Measured using a calibrated spring balance - newtonmeter
Equation for Weight - ANS- Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
,W=mg
What is weight directly proportional to? - ANS- Mass
What are free body diagrams? - ANS- Diagrams that show all the forces acting on an
object
What is the minimum number of forces acting on an object in real situations? - ANS- At
least 2 forces
What is the resultant force? - ANS- The single force that replaces multiple forces acting
at a single point
How is work done? - ANS- When a force moves an object through a distance, energy is
transferred and work is done on the object
Equation for 'Work Done' - ANS- Work done (J) = Force (N) x Distance (m)
W=Fs
What is 1J equal to? - ANS- 1Nm
What could happen when you apply a force to an object? - ANS- It may stretch,
compress or bend
What happens when an object is inelastically deformed? - ANS- The object won't return
to its original shape and length after the force has been removed
Equation for Force 1 - ANS- Force (N) = Spring Constant (N/m) x Extension (m)
F=ke
What is extension directly proportional to? - ANS- The force applied
F∝e
The stiffer the spring... - ANS- ...The greater the spring constant
What is the limit of proportionality? - ANS- The point at which extension is no longer
directly proportional to force
Equation for 'Moments' - ANS- Moment of a force (Nm) = Force (N) x Distance (m)
M=Fd
What is a moment? - ANS- The turning effect of a force
,When will an object not turn? - ANS- When the object is balanced - the total
anticlockwise moment equals the total clockwise moment about a pivot
What affects the size of a moment? - ANS- 1) The size of the force applied - a larger force
will produce a larger moment
2) The perpendicular distance from the pivot to the line of action of the force - any angle
smaller than 90° will result in a smaller distance, thus a smaller moment
What do levers do? - ANS- They increase the distance from the pivot at which the force
is applied
Do levers make it easier or harder to do work? - ANS- Easier to do work
What are gears and what do they do? - ANS- Circular discs with 'teeth' around their
edges
Their teeth interlock so that turning one causes another to turn in the opposite direction
They are used to transmit the rotational effect of a force from one place to another
What is pressure? - ANS- The force per unit area
Equation for Pressure - Surface of a fluid - ANS- Pressure (Pa) = Force normal to a
surface (N) / Area of that surface (m²)
p=F/A
What is the pressure of a fluid? - ANS- A force is exerted normal (at right angles) to any
surface in contact with the fluid
What is density? - ANS- A measure of the 'compactness' of a substance
Equation for Pressure - Liquid - ANS- Pressure (Pa) = Height of the column of liquid (the
depth)(m) x Density of the liquid (kg/m³) x Gravitational field strength (N/kg)
p=hρg
What is upthrust? - ANS- The force exerted on the bottom of the object is larger than the
force acting on the top of the object - the resultant force upwards on an object when it is
submerged in water
What is upthrust equal to? - ANS- The weight of fluid that has been displaced by the
object
Why do objects float? - ANS- The upthrust of the object is equal to the object's weight,
thus the force balances
It has a low density
, Why do objects sink? - ANS- The object's weight is more than the upthrust
It has a high density
Low density - ANS- If an object is less dense than the fluid it is placed in, it weighs less
than the equivalent volume of fluid
It will displace a volume of fluid that is equal to its weight before it is completely
submerged
High density - ANS- If an object is denser than the fluid it is placed in, it will be unable to
displace enough fluid to equal its weight, therefore its weight will be larger
How do submarines make use of upthrust? - ANS- To sink, large tanks are filled with
water to increase the weight of the submarine so that it is more than the upthrust
To float, the tanks are filled with compressed air to reduce the weight so that it is less
than the upthrust
What is atmospheric pressure? - ANS- A layer of air that surrounds Earth
It's created on a surface when air molecules collide with the surface
What is atmospheric pressure inversely proportional to? - ANS- Altitude (height above
Earth)
If the altitude increases, atmospheric pressure decreases and becomes less dense
What else happens when altitude increases? - ANS- There are fewer air molecules above
a surface as the height increases, therefore the weight of the air above it (which
contributes to atmospheric pressure) decreases
What is distance? - ANS- How far an object has moved
What is displacement? - ANS- It measures the distance and direction in a straight line
from an object's starting point to its finishing point
What is speed? - ANS- How fast you're going
What is velocity? - ANS- Speed (how fast you're going) in a given direction
Equation for Speed - ANS- Distance Travelled (m) = Speed (m/s) x Time (s)
s=vt
What is the typical speed of a person walking? - ANS- 1.5m/s
What is the typical speed of a person running? - ANS- 3m/s
What is the typical speed of a person cycling? - ANS- 6m/s
What are vectors? - ANS- Quantities that have a magnitude and a direction
What are scalars? - ANS- Quantities that only have a magnitude
Examples of vectors - ANS- Force
Velocity
Displacement
Acceleration
Momentum
Examples of scalars - ANS- Speed
Distance
Mass
Temperature
Time
What are contact forces? - ANS- Forces that act when two objects are touching
What are non-contact forces? - ANS- Forces that act without the need for two objects to
be touching
Examples of contact forces - ANS- Friction
Air resistance
Tension in ropes
Normal contact force
Examples of non-contact forces - ANS- Magnetic force
Gravitational force
Electrostatic force
What is mass? - ANS- The amount of material an object is made of
It is the same value everywhere
Measured using a mass balance
What is weight? - ANS- The force acting on an object due to gravity
It depends on the strength of the gravitational field at the location of the object
Measured using a calibrated spring balance - newtonmeter
Equation for Weight - ANS- Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
,W=mg
What is weight directly proportional to? - ANS- Mass
What are free body diagrams? - ANS- Diagrams that show all the forces acting on an
object
What is the minimum number of forces acting on an object in real situations? - ANS- At
least 2 forces
What is the resultant force? - ANS- The single force that replaces multiple forces acting
at a single point
How is work done? - ANS- When a force moves an object through a distance, energy is
transferred and work is done on the object
Equation for 'Work Done' - ANS- Work done (J) = Force (N) x Distance (m)
W=Fs
What is 1J equal to? - ANS- 1Nm
What could happen when you apply a force to an object? - ANS- It may stretch,
compress or bend
What happens when an object is inelastically deformed? - ANS- The object won't return
to its original shape and length after the force has been removed
Equation for Force 1 - ANS- Force (N) = Spring Constant (N/m) x Extension (m)
F=ke
What is extension directly proportional to? - ANS- The force applied
F∝e
The stiffer the spring... - ANS- ...The greater the spring constant
What is the limit of proportionality? - ANS- The point at which extension is no longer
directly proportional to force
Equation for 'Moments' - ANS- Moment of a force (Nm) = Force (N) x Distance (m)
M=Fd
What is a moment? - ANS- The turning effect of a force
,When will an object not turn? - ANS- When the object is balanced - the total
anticlockwise moment equals the total clockwise moment about a pivot
What affects the size of a moment? - ANS- 1) The size of the force applied - a larger force
will produce a larger moment
2) The perpendicular distance from the pivot to the line of action of the force - any angle
smaller than 90° will result in a smaller distance, thus a smaller moment
What do levers do? - ANS- They increase the distance from the pivot at which the force
is applied
Do levers make it easier or harder to do work? - ANS- Easier to do work
What are gears and what do they do? - ANS- Circular discs with 'teeth' around their
edges
Their teeth interlock so that turning one causes another to turn in the opposite direction
They are used to transmit the rotational effect of a force from one place to another
What is pressure? - ANS- The force per unit area
Equation for Pressure - Surface of a fluid - ANS- Pressure (Pa) = Force normal to a
surface (N) / Area of that surface (m²)
p=F/A
What is the pressure of a fluid? - ANS- A force is exerted normal (at right angles) to any
surface in contact with the fluid
What is density? - ANS- A measure of the 'compactness' of a substance
Equation for Pressure - Liquid - ANS- Pressure (Pa) = Height of the column of liquid (the
depth)(m) x Density of the liquid (kg/m³) x Gravitational field strength (N/kg)
p=hρg
What is upthrust? - ANS- The force exerted on the bottom of the object is larger than the
force acting on the top of the object - the resultant force upwards on an object when it is
submerged in water
What is upthrust equal to? - ANS- The weight of fluid that has been displaced by the
object
Why do objects float? - ANS- The upthrust of the object is equal to the object's weight,
thus the force balances
It has a low density
, Why do objects sink? - ANS- The object's weight is more than the upthrust
It has a high density
Low density - ANS- If an object is less dense than the fluid it is placed in, it weighs less
than the equivalent volume of fluid
It will displace a volume of fluid that is equal to its weight before it is completely
submerged
High density - ANS- If an object is denser than the fluid it is placed in, it will be unable to
displace enough fluid to equal its weight, therefore its weight will be larger
How do submarines make use of upthrust? - ANS- To sink, large tanks are filled with
water to increase the weight of the submarine so that it is more than the upthrust
To float, the tanks are filled with compressed air to reduce the weight so that it is less
than the upthrust
What is atmospheric pressure? - ANS- A layer of air that surrounds Earth
It's created on a surface when air molecules collide with the surface
What is atmospheric pressure inversely proportional to? - ANS- Altitude (height above
Earth)
If the altitude increases, atmospheric pressure decreases and becomes less dense
What else happens when altitude increases? - ANS- There are fewer air molecules above
a surface as the height increases, therefore the weight of the air above it (which
contributes to atmospheric pressure) decreases
What is distance? - ANS- How far an object has moved
What is displacement? - ANS- It measures the distance and direction in a straight line
from an object's starting point to its finishing point
What is speed? - ANS- How fast you're going
What is velocity? - ANS- Speed (how fast you're going) in a given direction
Equation for Speed - ANS- Distance Travelled (m) = Speed (m/s) x Time (s)
s=vt
What is the typical speed of a person walking? - ANS- 1.5m/s
What is the typical speed of a person running? - ANS- 3m/s
What is the typical speed of a person cycling? - ANS- 6m/s
