1

AP Physics B Equations

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Newtonian Mechanics

• Equation for uniformly-accelerated motion that is missing the variable: x (displacement)

• v = v₀ + at m/s• v = final velocity m/s• v₀ = initial velocity m/s• a = acceleration m/s2

• t = time s

3

Newtonian Mechanics

• Equation for uniformly-accelerated motion that is missing the variable: v (final velocity)

• x = x₀ + v₀t + ½at² m• x = final displacement m• x₀ = initial displacement m• v₀ = initial velocity m/s• a = acceleration m/s2

• t = time m

4

Newtonian Mechanics

• Equation for uniformly-accelerated motion that is missing the variable: t (time)

• v² = v₀² + 2a(x – x0) (m/s)2 • v = final velocity m/s• v0 = initial velocity m/s• a = acceleration m/s2

• x = final displacement m• x0 = initial displacement m

5

Newtonian Mechanics

• Equation for net force – Newton’s 2nd Law• ΣF = Fnet = ma N• F = force N• m = mass kg• a = acceleration m/s2

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Newtonian Mechanics

• Equation for the force of friction• Ffric ≤ μN N• F = force N• μ = coefficient of friction none• N = normal force N

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Newtonian Mechanics

• Equation for centripetal acceleration• ac = v2/r m/s2

• a = acceleration m/s2

• v = velocity m/s• r = radius or distance m

8

Newtonian Mechanics

• Equation for torque• τ = rF sin Θ Nm• τ = torque Nm• r = radius or distance m• F = force N• Θ = angle degrees

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Newtonian Mechanics

• Equation for momentum• p = mv kg m/s• p = momentum kg m/s• m = mass kg• v = velocity m/s

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Newtonian Mechanics

• Equation for impulse• J = F ∆t = ∆p kg m/s• J = impulse kg m/s• F = force N• t = time s• p = momentum kg m/s

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Newtonian Mechanics

• Equation for kinetic energy• K = ½ mv2 J = kg m2/s2

• K = kinetic energy J• m = mass kg• v = velocity m/s

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Newtonian Mechanics

• Equation for gravitational potential energy• ∆Ug = mgh J = kg m/s2 m• U = potential energy J• m = mass kg• g = gravitational acceleration m/s2

• h = height m

13

Newtonian Mechanics

• Equation for work done on a system• W = F ∆r cos Θ J = N m • W = work done on a systemJ• F = force N• r = radius or distance m• Θ = angle degrees

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Newtonian Mechanics

• Equation for average power• Pavg = W/∆t Watt = N / s• P = power Watt• W = work done on a systemN• t = time s

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Newtonian Mechanics

• Equation for instantaneous power• P = Fv cos Θ Watt = N/s• P = power W• v = velocity m/s• Θ = angle degrees

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Newtonian Mechanics

• Equation for Hooke’s Law• Fs = -kx N• F = force N• k = spring constant N/m• x = radius or distance m

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Newtonian Mechanics

• Equation for potential energy of a spring• Us = ½ kx2 N/m m2

• U = potential energy N/m m2

• k = spring constant N/m• x = radius or distance m

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Newtonian Mechanics

• Equation for period of a spring• Ts = 2π(m/k)1/2 s• T = period s• m = mass kg• k = spring constant N/m

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Newtonian Mechanics

• Equation for period of a pendulum• Tp = 2π(l/g)1/2 s• T = period s• l = length m• g = gravitational acceleration m/s2

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Newtonian Mechanics

• Equation for period and frequency• T = 1/f s• T = period s• f = frequency cycles = Hertz = cycles/s

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Newtonian Mechanics

• Equation for gravitational force – Law of Universal Gravitation

• Fg = - (Gm1m2)/r2 N• F = force N• G = gravitational constant Nm2/kg2

• m = mass kg• r = radius or distance m

22

Newtonian Mechanics

• Equation for gravitational potential energy• Ug = - (Gm1m2)/r J• F = force N• G = gravitational constant Nm2/kg2

• m = mass kg• r = radius or distance m