Physics paper 2
PH5
Scalar= magnitude only e.g. speed, distance, time energy
Vector= magnitude and direction e.g. velocity, displacement, acceleration, force, momentum
Contact force= when objects are physically touching e.g. friction, air resistance
Non contact force= objects that are physically separated e.g. gravitational force
Weight of an object is directly proportional to the mass of an object
Use newton meter to measure weight
Resultant force is the single force that is the same as all the forces acting on an object
Work done against friction causes a temperature increase
Objects bend, compress or stretch when force is applied
To change the shape of a stationary object, more than one force must be applied
Elastic deformation= object goes back to original shape when force is removed e.g. elastic band
Plastic deformation= object is permanently stretched when force is removed e.g squashed
plastic bottle
Hooke's Law= Extension of an elastic object is directly proportional to the force applied
Spring constant can be determined by finding gradient
Limit of proportionality= when Hooke's Law is no longer obeyed as extension is no longer
directly proportional to force applied e.g. when spring has been stretched too much so won't go
back to original shape
Distance= how far an object has moved (scalar)
Displacement= how far an object has moved and the direction it moved in (vector)
Walking 1.5 m/s
Running 3m/s
Cycling 6m/s
Speed of sound 330 m/s
Gradient of velocity-time graph= acceleration
Distance= area under graph
First law of motion If the resultant force on a stationary object is
0, the object will remain stationary
If the resultant force on a moving object is 0,
the object will continue moving at constant
velocity
Second law of motion Acceleration of an object is directly
proportional to it resultant force and inversely
proportional to the mass of the object
Third law of motion When two objects interact , the forces they
exert on each other are equal (magnitude)
and opposite (direction)
, Inertia= tendency of an object to continue in its current state of rest or motion
Inertial mass= How difficult it is to change the velocity of an object (ratio of force over
acceleration)
Stopping distance= thinking distance + braking distance
Thinking distance= distance vehicle travels during driver's reaction time
Braking distance= distance the vehicle travels under the braking force
Greater speed means greater stopping distance
Typical reaction time is 0.2-0.9s
Braking distance is affected by poor road and weather conditions
If velocity is doubled, the stopping distance will increase by a factor of 4
Friction between tyres and brake pads cause kinetic energy of vehicle to decrease and brake
pads to increase in temperature
Faster the vehicle travels = greater braking force required = greater braking
Dangers of greater deceleration:
- Brakes can overheat
- Driver may lose control
Reaction time practical
- Person sits at desk with hand out
- Hold ruler up to hand and line up 0 cm on ruler with the person’s thumb and forefinger
- When ruler gets released, they have to catch it as quickly as possible
- Drop ruler but don’t tell person it’s dropped
- Measure distance travelled by ruler
- Calculate final velocity: (final velocity)2 - (initial velocity)2 = 2 x acceleration x distance
- Acceleration = due to gravity so 9.8m/s2
- Calculate time taken: change in velocity/ time
- Repeat and calculate mean
PH6
Waves= oscillations or vibrations about a point
Transverse waves Longitudinal waves
- Vibrations at right angles to direction - Vibrations parallel to direction of
of energy transfer energy transfer
- Waves go up and down - Waves go side to side
- Water waves / electromagnetic waves - Sound waves/ ultrasound
- Height from peak/ trough to - Compression = high pressure where
equilibrium position= amplitude particles are close together
- Refraction= low pressure where
particles are far apart
Amplitude= maximum displacement of a point on a wave from its rest position
Period= time taken for a wave to complete one cycle
Wave speed= speed at which energy is transferred through a medium: frequency x wavelength
Frequency- number of waves passing a point per second
Wavelength= distance between a point on one wave and the next point on the same wave
PH5
Scalar= magnitude only e.g. speed, distance, time energy
Vector= magnitude and direction e.g. velocity, displacement, acceleration, force, momentum
Contact force= when objects are physically touching e.g. friction, air resistance
Non contact force= objects that are physically separated e.g. gravitational force
Weight of an object is directly proportional to the mass of an object
Use newton meter to measure weight
Resultant force is the single force that is the same as all the forces acting on an object
Work done against friction causes a temperature increase
Objects bend, compress or stretch when force is applied
To change the shape of a stationary object, more than one force must be applied
Elastic deformation= object goes back to original shape when force is removed e.g. elastic band
Plastic deformation= object is permanently stretched when force is removed e.g squashed
plastic bottle
Hooke's Law= Extension of an elastic object is directly proportional to the force applied
Spring constant can be determined by finding gradient
Limit of proportionality= when Hooke's Law is no longer obeyed as extension is no longer
directly proportional to force applied e.g. when spring has been stretched too much so won't go
back to original shape
Distance= how far an object has moved (scalar)
Displacement= how far an object has moved and the direction it moved in (vector)
Walking 1.5 m/s
Running 3m/s
Cycling 6m/s
Speed of sound 330 m/s
Gradient of velocity-time graph= acceleration
Distance= area under graph
First law of motion If the resultant force on a stationary object is
0, the object will remain stationary
If the resultant force on a moving object is 0,
the object will continue moving at constant
velocity
Second law of motion Acceleration of an object is directly
proportional to it resultant force and inversely
proportional to the mass of the object
Third law of motion When two objects interact , the forces they
exert on each other are equal (magnitude)
and opposite (direction)
, Inertia= tendency of an object to continue in its current state of rest or motion
Inertial mass= How difficult it is to change the velocity of an object (ratio of force over
acceleration)
Stopping distance= thinking distance + braking distance
Thinking distance= distance vehicle travels during driver's reaction time
Braking distance= distance the vehicle travels under the braking force
Greater speed means greater stopping distance
Typical reaction time is 0.2-0.9s
Braking distance is affected by poor road and weather conditions
If velocity is doubled, the stopping distance will increase by a factor of 4
Friction between tyres and brake pads cause kinetic energy of vehicle to decrease and brake
pads to increase in temperature
Faster the vehicle travels = greater braking force required = greater braking
Dangers of greater deceleration:
- Brakes can overheat
- Driver may lose control
Reaction time practical
- Person sits at desk with hand out
- Hold ruler up to hand and line up 0 cm on ruler with the person’s thumb and forefinger
- When ruler gets released, they have to catch it as quickly as possible
- Drop ruler but don’t tell person it’s dropped
- Measure distance travelled by ruler
- Calculate final velocity: (final velocity)2 - (initial velocity)2 = 2 x acceleration x distance
- Acceleration = due to gravity so 9.8m/s2
- Calculate time taken: change in velocity/ time
- Repeat and calculate mean
PH6
Waves= oscillations or vibrations about a point
Transverse waves Longitudinal waves
- Vibrations at right angles to direction - Vibrations parallel to direction of
of energy transfer energy transfer
- Waves go up and down - Waves go side to side
- Water waves / electromagnetic waves - Sound waves/ ultrasound
- Height from peak/ trough to - Compression = high pressure where
equilibrium position= amplitude particles are close together
- Refraction= low pressure where
particles are far apart
Amplitude= maximum displacement of a point on a wave from its rest position
Period= time taken for a wave to complete one cycle
Wave speed= speed at which energy is transferred through a medium: frequency x wavelength
Frequency- number of waves passing a point per second
Wavelength= distance between a point on one wave and the next point on the same wave
