Physics Equations

Question 1

How do you calculate resistance from a graph?

Answer 1

Resistance = 1/Gradient

Question 2

Equation for thermal energy transferred:

Answer 2

Thermal energy transferred = Mass x Specific heat capacity x Temperature change

Question 3

Acceleration? (+ unit)

Answer 3

Change in velocity / Time (m/s^2)

Question 4

Final velocity, initial velocity, etc.

Answer 4

Final velocity^2 - Initial velocity^2 = 2 x Acceleration x Distance

Question 5

Change in kinetic energy:

Answer 5

(Mass x (V^2-v^2)) /2

Question 6

Gravitational potential energy:

Answer 6

Mass x Gravitational field strength x Height

Question 7

Power, Current, and Resistance

Answer 7

Power = Current^2 x Resistance

Question 8

Work done, Charge, and Voltage

Answer 8

Work done = Charge x Voltage

Question 9

LDR - resistance?

Answer 9

As light intensity increases, resistance decreases

Question 10

Thermistor - resistance?

Answer 10

As heat increases, resistance decreases

Question 11

Diode - function?

Answer 11

Only allow current to flow one way. Converts AC electricity to DC.

Question 12

Voltage, Current, and Resistance

Answer 12

Voltage = Current x Resistance

Question 13

Charge, Current, and Time

Answer 13

Charge = Current x Time

Question 14

Energy, Current, Voltage, and Time

Answer 14

Energy = Current x Voltage x Time

Question 15

Power, Current, and Voltage

Answer 15

Power = Current x Voltage

Question 16

How do you get the voltage from a Current-Voltage graph?

Answer 16

The steeper the gradient, the lower the resistance

Question 17

How do you calculate total resistance in series circuits?

Answer 17

Sum of all resistors

Question 18

How do you calculate total current in parallel circuits?

Answer 18

Sum of all ammeters

Question 19

How do you calculate total voltage in series circuits?

Answer 19

Sum of all voltmeters

Question 20

How do you calculate the total resistance in parallel circuits?

Answer 20

Reciprocal of all resistors added together (Total resistance < Lowest resistor)

Question 21

Convert N/cm into N/m

Answer 21

1N/cm = 100N/m

Question 22

Mechanical work done

Answer 22

Work done = Force x Distance

Question 23

Electrical work done

Answer 23

Electrical work done = Power x Time

Question 24

Efficiency

Answer 24

Useful energy output / Total energy input

Question 25

Kinetic Energy

Answer 25

0.5 x Mass x Velocity^2

Question 26

Pressure (+unit)

Answer 26

Pressure = Force / Area (Pascal or N/m)

Question 27

Thermal energy for a change of state

Answer 27

Thermal energy for a change of state = Mass x Specific latent heat

Question 28

Gas volumes (constant)

Answer 28

Constant = Volume x Pressure

Question 29

Force, spring constant, and extension

Answer 29

Force = spring constant x extension

Question 30

Pressure in liquids

Answer 30

Height x Density x Gravitational field strength

Question 31

Momentum, Mass, and Velocity

Answer 31

Momentum = Mass x Velocity

Question 32

Force, Change in Momentum, and Time

Answer 32

Force = Change in Momentum / Time

Question 33

Resultant Force

Answer 33

Resultant force = Mass x Acceleration

Question 34

Wave Speed

Answer 34

Wave speed = Frequency x Wavelength

Question 35

Magnification

Answer 35

Image / Object

Question 36

Period

Answer 36

1 / Frequency

Question 37

Force on a conductor (at right angles to a magnetic field)

Answer 37

Magnetic Flux Density x Current x Length

Question 38

Elastic potential energy

Answer 38

0.5 x spring constant x extension

Question 39

Moment

Answer 39

Moment = Force x Distance