AQA Physics (9-1) Revision
Year 9 Module 1: Forces and their Interactions
➔ 4.5.1.1: Scalar and Vector quantities
Scalar quantities only have magnitude. e.g temperature, mass, energy, distance, speed
Vector quantities have magnitude and direction. e.g force, displacement, velocity, acceleration, momentum
A vector quantity may be represented by an arrow. The length of the arrow represents the magnitude, and the
direction of the arrow represents the direction of the vector quantity
➔ 4.5.1.2: Contact and non-contact forces
A force is a push or pull that acts on an object due to the interaction with another object. It is a vector quantity.
All forces between objects are either:
→ Contact forces: The objects are physically touching
→ Non-contact forces: The objects are physically separated
Examples: Contact: friction, air resistance, tension, normal contact force
Non-contact: gravitation force (weight), electrostatic force, magnetic force
➔ 4.5.1.3: Gravity
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
The weight of an object may be considered to act at a single point referred to as the object’s ‘centre of mass’.
The weight of an object and mass of an object are directly proportional.
Weight is measured using a calibrated spring balance (newtonmeter)
➔ 4.5.1.4: Resultant Force
A number of forces acting on an object may be replaced by a single force that has the same effect as all the
original forces acting together. This single force is called the resultant force.
A single force can be resolved into two components acting at right angles to each other. The two-component
forces together have the same effect as the single force.
➔ 4.5.3: Forces and Elasticity
More than one force must be applied to change the shape of a stationary object by stretching, bending or
compressing, because a single force would simply cause the object to move in the direction in which the force
were to be applied.
Elastic deformation: An object undergoing elastic deformation will return to its original shape once any forces
being applied to it are removed
Inelastic deformation: An object undergoing inelastic deformation will not return to its original shape once the
shapes being applied on it are removed
,Force (N) = Spring constant (N/m) x extension (m)
➔ 4.5.4: Moments, levers and gears
A moment is the turning effect of a force. The size of a moment is defined by the equation:
Moment (Nm) = Force (N) x perpendicular distance from the pivot to line of action (m)
If an object is balanced, the total clockwise moment about a pivot equals the total anticlockwise moment about
that pivot.
Levers transmit the rotational effect of forces by increasing the perpendicular distance from the pivot at which a
force is applied relative to that of the load, causing a larger force to act upon the load than is applied to the lever
Year 9 Module 2: Introduction to Energy
➔ 4.1.1.1: Energy stores and systems
A system is an object or group of objects.
Energy can be transferred in 4 ways:
→ Mechanical work: a force moving an object through a distance
→ Electrical work: charges moving due to a potential difference
→ heating - due to temperature difference caused electrically or by chemical reaction
→ radiation - energy tranferred as a wave
Gravity
Kinetic
Thermal
, Elastic
Chemical
➔ 4.1.1.2: Changes in energy
Kinetic Energy (J) = 0.5 x mass (kg) x speed2 (m/s) Ek= ½ mv2
Elastic Potential Energy (J) = 0.5 x spring constant (N/m) x extension2 (m) Ee= ½ke2
Gravitational Potential Energy(J) = mass (kg) x gravitational field strength (N/kg) x height (m) E p= mgh
➔ 4.5.2: Work done and energy transfer
Work done (J) = Force (N) x distance (m) W= Fd
1 Joule = 1 Newton-metre
➔ 4.1.1.4: Power
Power is defined as the rate at which energy is transferred or the rate at which work is done.
Power (W) = Work done (J) / Time (s) = Energy transferred (J) / Time (s) P = W/T = E/T
An energy transfer of 1 joule per second is equal to a power of 1 watt
Module 3: Energy Transfers
➔ 4.1.2.1: Energy transfers in a system
Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed.
The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction across
the material.
➔ 4.1.1.2: Efficiency
Efficiency = Useful output energy transfer/ total input energy transfer
Efficiency = useful power output / total power input
➔ 4.1.3: National and global energy resources
Year 9 Module 1: Forces and their Interactions
➔ 4.5.1.1: Scalar and Vector quantities
Scalar quantities only have magnitude. e.g temperature, mass, energy, distance, speed
Vector quantities have magnitude and direction. e.g force, displacement, velocity, acceleration, momentum
A vector quantity may be represented by an arrow. The length of the arrow represents the magnitude, and the
direction of the arrow represents the direction of the vector quantity
➔ 4.5.1.2: Contact and non-contact forces
A force is a push or pull that acts on an object due to the interaction with another object. It is a vector quantity.
All forces between objects are either:
→ Contact forces: The objects are physically touching
→ Non-contact forces: The objects are physically separated
Examples: Contact: friction, air resistance, tension, normal contact force
Non-contact: gravitation force (weight), electrostatic force, magnetic force
➔ 4.5.1.3: Gravity
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
The weight of an object may be considered to act at a single point referred to as the object’s ‘centre of mass’.
The weight of an object and mass of an object are directly proportional.
Weight is measured using a calibrated spring balance (newtonmeter)
➔ 4.5.1.4: Resultant Force
A number of forces acting on an object may be replaced by a single force that has the same effect as all the
original forces acting together. This single force is called the resultant force.
A single force can be resolved into two components acting at right angles to each other. The two-component
forces together have the same effect as the single force.
➔ 4.5.3: Forces and Elasticity
More than one force must be applied to change the shape of a stationary object by stretching, bending or
compressing, because a single force would simply cause the object to move in the direction in which the force
were to be applied.
Elastic deformation: An object undergoing elastic deformation will return to its original shape once any forces
being applied to it are removed
Inelastic deformation: An object undergoing inelastic deformation will not return to its original shape once the
shapes being applied on it are removed
,Force (N) = Spring constant (N/m) x extension (m)
➔ 4.5.4: Moments, levers and gears
A moment is the turning effect of a force. The size of a moment is defined by the equation:
Moment (Nm) = Force (N) x perpendicular distance from the pivot to line of action (m)
If an object is balanced, the total clockwise moment about a pivot equals the total anticlockwise moment about
that pivot.
Levers transmit the rotational effect of forces by increasing the perpendicular distance from the pivot at which a
force is applied relative to that of the load, causing a larger force to act upon the load than is applied to the lever
Year 9 Module 2: Introduction to Energy
➔ 4.1.1.1: Energy stores and systems
A system is an object or group of objects.
Energy can be transferred in 4 ways:
→ Mechanical work: a force moving an object through a distance
→ Electrical work: charges moving due to a potential difference
→ heating - due to temperature difference caused electrically or by chemical reaction
→ radiation - energy tranferred as a wave
Gravity
Kinetic
Thermal
, Elastic
Chemical
➔ 4.1.1.2: Changes in energy
Kinetic Energy (J) = 0.5 x mass (kg) x speed2 (m/s) Ek= ½ mv2
Elastic Potential Energy (J) = 0.5 x spring constant (N/m) x extension2 (m) Ee= ½ke2
Gravitational Potential Energy(J) = mass (kg) x gravitational field strength (N/kg) x height (m) E p= mgh
➔ 4.5.2: Work done and energy transfer
Work done (J) = Force (N) x distance (m) W= Fd
1 Joule = 1 Newton-metre
➔ 4.1.1.4: Power
Power is defined as the rate at which energy is transferred or the rate at which work is done.
Power (W) = Work done (J) / Time (s) = Energy transferred (J) / Time (s) P = W/T = E/T
An energy transfer of 1 joule per second is equal to a power of 1 watt
Module 3: Energy Transfers
➔ 4.1.2.1: Energy transfers in a system
Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed.
The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction across
the material.
➔ 4.1.1.2: Efficiency
Efficiency = Useful output energy transfer/ total input energy transfer
Efficiency = useful power output / total power input
➔ 4.1.3: National and global energy resources
