Equations

Question 1

What is the equation for work done?

Answer 1

Work done (J) = force applied (N) x distance (M)

Question 2

What is the equation for gravitational potential energy?

Answer 2

Gravitational potential energy (J) = mass (kg) x gravitational field strength (N/kg) x height (m)

Question 3

What is the equation for kinetic energy?

Answer 3

Kinetic energy (J) = 1/2 x mass (kg) x velocity^2 (m/s)

Question 4

What is the equation for elastic potential energy?

Answer 4

Elastic potential energy (J) = 1/2 x spring constant (N/m) x extension^2 (m)

Question 5

What is the equation for efficiency?

Answer 5

Useful output energy (J) / total input energy (J)

Question 6

What is the equation for power relating to energy and time?

Answer 6

Power (W) = energy transferred (J) / time taken (s)

Question 7

What is the equation for wasted power?

Answer 7

Power wasted = total power in - useful power out

Question 8

What is the equation for specific heat capacity?

Answer 8

Energy transferred (J) = mass (kg) x specific heat capacity (J/kg degrees C) x temperature change (degrees C)

Question 9

What is the equation involving voltage, energy transferred and charge?

Answer 9

Potential difference (V) = energy transferred (J) / charge (Q)

Question 10

What is the equation for resistance?

Answer 10

Resistance (ohms) = potential difference (V) / Current (A)

Question 11

What is the equation for resistance in a series?

Answer 11

Total resistance = sum of resistance of all components

Question 12

What is the equation for current?

Answer 12

Current (A) = potential difference (V) / component resistance (ohms)

Question 13

What is the equation linking power, current and voltage?

Answer 13

Power (W) = Current (A) x Potential difference (V)

Question 14

What is the equation linking power, current and resistance?

Answer 14

Power (W) = current^2 (A) x resistance (ohms)

Question 15

What is the equation linking charge and current?

Answer 15

Charge flow (C) = Current (A) x time (s)

Question 16

What is the equation for density?

Answer 16

Density (kg/m3) = mass (kg) / volume (m3)

Question 17

What is the equation for latent heat?

Answer 17

Specific latent heat of fusion/vapourisation (J/kg) = energy (J) / mass (kg)

Question 18

What is the equation for Boyle’s Law?

Answer 18

Pressure (Pa) x volume (m3) = constant

Question 19

What is the equation for moments of forces?

Answer 19

Moment (Nm) = Force (N) x perpendicular distance from the line of action of the force to the pivot (m)

Question 20

What is the principle of moments?

Answer 20

The sum of all clockwise moments = The sum of all anticlockwise moments

Question 21

What is the equation for speed?

Answer 21

Speed (m/s) = distance (m) / time (s)

Question 22

What is the equation for acceleration?

Answer 22

Acceleration (m/s) = change in velocity (m/s) / time taken (s)

Question 23

What is the equation for resultant force?

Answer 23

Resultant force (N) = mass (kg) x acceleration (m/s^2)

Question 24

What is the equation for inertia?

Answer 24

Inertial mass = force / acceleration

Question 25

What is the equation for weight?

Answer 25

Weight (N) = mass (kg) x gravitational field strength (N/kg)

Question 26

What is stopping distance?

Answer 26

Stopping distance = thinking distance + braking distance

Question 27

What is the equation for momentum?

Answer 27

Momentum (kg m/s) = mass (kg) x velocity (m/s)

Question 28

What is the equation for force using mass, change in velocity and time taken?

Answer 28

Force (N) = (mass (kg) x change in velocity (m/s)) / time taken (s)

Question 29

What is the equation for Hooke’s Law?

Answer 29

Force applied (N) = spring constant (N/m) x extension (m)

Question 30

What is the equation for density in a liquid?

Answer 30

Pressure (Pa) = height (m) x density (kg/m3) x gravitational field strength (N/kg)