A Level Physics

Front 1

Capacitance definition

Back 1

charge stored per unit potential difference

Front 2

Capacitance graphs: Q against V
(gradient and area)

Back 2

Gradient is capacitance : C=Q/V

Area under is energy stored by capacitor

Front 3

Capacitance Graphs: V against Q
(gradient and area)

Back 3

Gradient is 1/capacitance

Area under is energy stored by capacitor

Front 4

Derivation of E=½QV

Back 4

(change in W) = V x (change in Q) explained (1)
energy stored = total work done in charging = charge x average voltage (1)
energy stored = work done (= ½QV) (1)

Front 5

Graph description of Energy stored against voltage

Back 5

Energy = ½CV^2
Exponential curve upwards

Energy Proportional to V^2
Straight diagonal upwards, through origin

Front 6

Time Constant Definition

Back 6

Time taken for the voltage (or charge or current) to fall to 1/e of its original value

Front 7

Finding time constant from a graph of Potential Difference (V) against time (t) [STEP 1]

Back 7

[STEP 1] Calculate 1/e of initial Voltage, V

Front 8

Finding time constant from a graph of Potential Difference (V) against time (t) [STEP 2]

Back 8

[STEP 2] Locate value on graph, time taken is Time constant

Front 9

Re-arrange V=Vo e^-t/RC

Back 9

[1] Divide both by Vo | V/Vo = e^-t/RC
[2] Log (ln) both sides | ln(V/Vo) = -t/RC

Front 10

Finding time constant from a graph of ln (v) against time. [Given that ln(V/Vo) = -t/RC]

Back 10

[3] Break up the log | ln(V) - ln(Vo) = -t/RC
[4] Into form like y=mx+c | ln(V) = {-1/RC}{t}+{ln(Vo)}

Front 11

Finding time constant from a graph of ln (v) against time. [In form y=mx+c || ln(V) = {-1/RC}{t}+{ln(Vo)} ]

Back 11

Gradient is -t/RC & Intercept is ln(Vo)
Time Constant (RC) = 1/Gradient

Front 12

Newton’s 1st Law

Back 12

An object remains at rest or in uniform motion unless acted on by a force

Front 13

Newton’s 2nd Law

Back 13

The rate of change of momentum of an object is proportional to the resultant force on it

Front 14

Newton’s 3rd Law

Back 14

When two objects interact they exert equal and opposite forces on each other

Front 15

Force (in terms of momentum change)

Back 15

Force = rate of change of momentum. VECTOR

Front 16

Units of momentum

Back 16

kgms^-1

Front 17

Units of rate of change of momentum

Back 17

kgms^-2

Front 18

Impulse, I

Back 18

Force x time for which the force acts (Ft)
Hence Impulse = change of momentum. VECTOR

Front 19

Units of Impulse, I

Back 19

Ns or kgms-1

Front 20

Graphical representations of charging a capacitor against time

Back 20

Front 21

Graphical representations of discharging a capacitor against time

Back 21

Front 22

Area under a graph of force against time

Back 22

change in momentum (p) or Impulse I

Front 23

Principle of conservation of linear momentum definition

Back 23

In a collision (or explosion) the total momentum before equals the total momentum after, providing no external forces are acting.

Front 24

Elastic collision definition

Back 24

A collision where kinetic energy is conserved

Front 25

Inelastic collision definition

Back 25

A collision where kinetic energy is not conserved
Note: TOTAL Energy is still conserved.

Front 26

Angular speed, 'w'

Back 26

angle turned through per second (SCALAR)

Front 27

Units of Angular speed 'w'

Back 27

rad s^-1

Front 28

Angular speed of earth

Back 28

Front 29

Centripetal Force

Back 29

RESULTANT force acting towards the centre of the circular path.

Front 30

Conditions for SHM (simple harmonic motion)

Back 30

1. Acceleration is proportional to displacement
2. Acceleration is in the opposite direction to displacement OR acceleration always acts towards the equilibrium position.

Front 31

Back 31

1. acceleration is always proportional to displacement (a proportional to x) and hence a = kx, where k is a constant (2[pi]f)^2

Front 32

Graph of acceleration against displacement

Back 32

Front 33

Graph of displacement against time

Back 33

Gradient of a displacement against time graph is VELOCITY

Front 34

Graphical representations linking x (displacement), v (velocity), a (acceleration) and t (time)

Back 34

Front 35

Conditions for the time period equation of a pendulum

Back 35

Time period equation for a pendulum id only true for oscillations with a SMALL amplitude, which includes angular displacements less than 10 degrees.

Front 36

Dependence of time period on amplitude of an oscillation

Back 36

The time period of an oscillation in SHM is INDEPENDANT of the amplitude.

Front 37

Variation of Potential energy and Kinetic energy with displacement

Back 37