Physical World

Formulas for Test 2

Speed
or velocity = change in distance/change in time, v = d/t [Units: m/s]

Acceleration
= change in velocity/change in time, a= (v_{f}
- v_{i})/t [Units: m/s/s or
m/s^{2}]

For
acceleration under gravity (starting from rest at time t = 0s)

v =
gt

d =
0.5gt^{2}

Net
force, F_{net} = ma [Units: N]

Weight,
W = mg [Units: N]

Momentum,
p = mv
[Units: kg m/s]

Impulse = F_{net}t = change in momentum =
p_{f} - p_{i}

Kinetic
energy, KE = 0.5mv^{2}
[Units: J]

Gravitational
potential energy, GPE = mgh [Units: J]

Work,
W = Fd [Units: J]

Gravitational
force, F = GMm/r^{2} [Units: N]

Acceleration
due to gravity ** at the surface of a
planet**, g = GM/r