Formulas

Question 1

Average speed (ms-1) =

Answer 1

distance (m) / time (s)

Question 2

Average velocity (ms-1) =

Answer 2

displacement (m) / time (s)

Question 3

Acceleration (ms-2) =

Answer 3

= final velocity (ms-1) – initial velocity(ms-1) / time (s)

Question 4

Weight (N) =

Answer 4

mass (kg) × gravitational field strength (ms-2)
Note: Earth’s gravitational field strength = 10 ms-2

Question 5

Force (N) =

Answer 5

mass (kg) × acceleration (ms-2)

Question 6

Density (kgm-3) =

Answer 6

mass (kg) / volume (m3)

Question 7

Hooke’s law:

Answer 7

Force (N) = constant (Nm-1) ×
extension (m)

Question 8

Pressure (Pa) =

Answer 8

force (N) / area (m2)

Question 9

Fluid Pressure (Pa) =

Answer 9

density (kgm-3) × gravitational field strength (ms-2 or Nkg-1) × height (m)

Question 10

Work (J) =

Answer 10

force (N) × distance moved (m)

Question 11

Power (W) =

Answer 11

work (J) / time (s)

Question 12

Kinetic Energy (J) =

Answer 12

½ × mass (kg) × velocity2 (ms-1)

Question 13

Gravitational potential energy (J) =

Answer 13

mass (kg) × gravitational field strength (ms-2 or Nkg-1) × height (m)

Question 14

Efficiency (%) =

Answer 14

useful power output (W) × 100 / total power input (W)

Question 15

Efficiency (%) =

Answer 15

useful energy output (J) × 100 / total energy input (J)

Question 16

Moment (Nm) =

Answer 16

force (N) × perpendicular distance from pivot (m)

Question 17

Sum of clockwise moments (Nm) =

Answer 17

sum of anticlockwise moments (Nm)

Question 18

Momentum (kgms-1) =

Answer 18

mass (kg) × velocity (ms-1)

Question 19

Force (N) =

Answer 19

change in momentum (kgms-1) / time (s)

Question 20

Impulse (kgms-1 or Ns) =

Answer 20

change in momentum (kgms-1)

Question 21

Centripetal Force (N) =

Answer 21

mass (kg) × velocity2 (ms-1) / radius (m)

Question 22

Energy (J) =

Answer 22

mass (kg) × specific heat capacity (Jkg1°C-1) × temperature change (°C)

Question 23

Thermal capacity (J°C-1) =

Answer 23

mass (kg) × specific heat capacity (Jkg-1°C-1)

Question 24

Energy transferred (J) =

Answer 24

mass (kg) × specific latent heat (Jkg-1)