Physical World 1 - 11.30am

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= (vf - vi)/t     [Units: m/s/s or m/s2]


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

v = gt

d = 0.5gt2


Newton's second law of motion

Net force, Fnet = ma       [Units: N]


Weight, W = mg               [Units: N]


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


Impulse = Fnett = change in momentum = pf - pi


Kinetic energy, KE = 0.5mv2         [Units: J]


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


Work, W = Fd        [Units: J]


Gravitational force, F = GMm/r2           [Units: N]


Acceleration due to gravity at the surface of a planet, g = GM/r2