Formulas for Test 4
Test 4
will cover homeworks 16 to 21 (i.e. Chaps. 22, 23,
24, 25, 26, 28, 29)
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): g = 10m/s2
v = gt
d = 0.5gt2
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 = GM1M2/r2
[Units: N]
For molecules at a particular temperature T, KE = 0.5mv2
= 3kBT/2
Heat energy, Q = mcDT [Units: J]
Heat energy, Q = mL [Units: J]
Wave speed, v = fl
[Units: m/s]
Wave frequency, f = 1/T where T is the period in seconds [Units for frequency: Hz = 1/s]
Coulomb's Law (force between charged particles), F = kq1q2/r2 [Units: N]
Electrical potential energy, EPE = V q [Units: J]
Current, I = q/t [Units: A]
Ohm's Law, V = IR [Units: V]
Power, P = EPE/t = V I [Units: W = J/s]
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Quantities and units
(in brackets)
distance, d (m)
time, t (s)
speed, v (m/s)
acceleration, a (m/s2), g (m/s2)
force, F (N); weight W(N)
mass, m (kg)
momentum, p (kg m/s)
energy, KE, GPE, EPE (J)
work, W (J)
heat, Q (J)
specific heat capacity, c (J/kg C)
latent heat, L (J/kg)
temperature, T (C or K)
frequency, f (Hz or 1/s)
wavelength, l (m)
voltage, V (V, volts)
charge, q (C, coulombs)
current, I (A, amps)
resistance, R (W, ohms)
power, P (W, watts)
*************************************************************************************
USEFUL DATA:
Speed of sound in air = 330m/s
Speed of light in a vacuum (or in air) = 3 x 108m/s
= 300,000,000 m/s