Formulas Flashcards
Average speed (ms-1) =
distance (m) / time (s)
Average velocity (ms-1) =
displacement (m) / time (s)
Acceleration (ms-2) =
= final velocity (ms-1) – initial velocity(ms-1) / time (s)
Weight (N) =
mass (kg) × gravitational field strength (ms-2)
Note: Earth’s gravitational field strength = 10 ms-2
Force (N) =
mass (kg) × acceleration (ms-2)
Density (kgm-3) =
mass (kg) / volume (m3)
Hooke’s law:
Force (N) = constant (Nm-1) ×
extension (m)
Pressure (Pa) =
force (N) / area (m2)
Fluid Pressure (Pa) =
density (kgm-3) × gravitational field strength (ms-2 or Nkg-1) × height (m)
Work (J) =
force (N) × distance moved (m)
Power (W) =
work (J) / time (s)
Kinetic Energy (J) =
½ × mass (kg) × velocity2 (ms-1)
Gravitational potential energy (J) =
mass (kg) × gravitational field strength (ms-2 or Nkg-1) × height (m)
Efficiency (%) =
useful power output (W) × 100 / total power input (W)
Efficiency (%) =
useful energy output (J) × 100 / total energy input (J)
Moment (Nm) =
force (N) × perpendicular distance from pivot (m)
Sum of clockwise moments (Nm) =
sum of anticlockwise moments (Nm)
Momentum (kgms-1) =
mass (kg) × velocity (ms-1)
Force (N) =
change in momentum (kgms-1) / time (s)
Impulse (kgms-1 or Ns) =
change in momentum (kgms-1)
Centripetal Force (N) =
mass (kg) × velocity2 (ms-1) / radius (m)
Energy (J) =
mass (kg) × specific heat capacity (Jkg1°C-1) × temperature change (°C)
Thermal capacity (J°C-1) =
mass (kg) × specific heat capacity (Jkg-1°C-1)
Energy transferred (J) =
mass (kg) × specific latent heat (Jkg-1)
