SAT II Physics/ AB Physics B

kinematics

v� = v? + at
v�� = v?� + 2a?x
?x = v?t + �at�
?x = v�t - �at�
?x = �(v� + v?)t

resultant

r = ?(x� + y�)

x vector

x = r(cos?)

y vector

y = r(sin?)

polar angle

? = tan?�(y/x)

work

W = F?x(cos?)

Newton's 1st law of motion

An object in motion will remain in motion indefinitely unless acted on by an outside force
***Inertia

Newton's 2nd law of motion

F = ma
***Most important mechanics equation

Newton's 3rd law of motion

For every action, there is an equal and opposite reaction
***Action-reaction pairs

force of gravity

F = (Gm?m?)/r�

force of friction

F = (�k)(Fn)

kinetic energy

KE = �mv�

work-energy theorem

w = ?KE

gravitational potential energy

?PE = - W = mgh
"W" is the work due to gravity

potential energy of a satellite

U = -(GMm)/r

kinetic energy of a satellite

K = (GMm)/2r

mechanical energy of a satellite

ME = -(GMm)/2r

conservation of total energy

ME? = ME?

power

P = W/t

momentum

p = mv

force

F = ?p/?t

impulse

J = ?p = F?t

conservation of linear momentum

p = p'
(mtotal)?(vtotal)? = (mtotal)?(vtotal)?

centripetal acceleration

ac = v�/r
***not an actual, physical quantity

centripetal force

Fc = (mv�)/r
***not an actual, physical quantity

center of mass

x = (m?x? + m?x? + ...)/(mtotal)

torque

t = rFsin?
r = distance from pivot to the force's point of application

angular velocity

? = ??/?t

angular acceleration

? = ??/?t

angular displacement

?? = ?s/r
s = r?

linear velocity

v = r?

linear acceleration

a = r?

angular centripetal acceleration

ac = ?�r

Kepler's 1st law

The orbit of each planet is an ellipse and the sun is at one focus
***Remember the length of the semimajor axis usually = the R value

Kepler's 2nd law

An imaginary line from the sun to a moving planet sweeps out equal areas
***This implies that the closer a satellite/planet gets to the sun/planet, the faster its orbit becomes (so it can cover the same area as it would farther away, in the same amount of time).

Kepler's 3rd law

(T?)�/(T?)� = (R?)�/(R?)�
The ratio of the square of a planet's period of revolution (the time for one complete orbit) to the cube of its average distance from the sun is a constant that is the same for all planets.

Coulomb's law

|F| = (k|q?q?|)/r

electric field

E = F/q

electric field

E = V/d

electric field

E = (kq)/r�

important fact

There can be no electric field within the body of a conductor

electric potential energy

?U = -W
W = work applied by electric force

electric potential difference

?V = ?U/q

electric potential (voltage)

V = (kq)/r

capacitance

C = q/?V

capacitance

C = (??A)/d

parallel capacitance

C? = C?+C?

series capacitance

1/C? = 1/C? + 1/C?

dielectric

Increases the capacitance of a capacitor
***Is often an insulator

current

I = ?q/?t

resistance

R = ?V/I

power

P = IV
P = I�R
P = V�/R

series resistance

R? = R? + R?

parallel current

I? = I? + I?

series current

I? = I? = I?

parallel resistance

1/R? = 1/R? + 1/R?

magnetic force

F = |q|vBsin?
***F is the magnetic force, perpendicular to magnetic field

magnetic field rules

Magnetic force F is always perpendicular to both v and B
Magnetic forces cannot change the speed of an object, only its direction
The magnetic field does no work on any charge

magnetic force

F = I?Bsin?
? = length

EMF

? = B?v = ??/?t

flux

? = BAcos?

inverse

Electric PE vs. Capacitance
What is the relationship?

resistance

R = (?L)/A
***? is rho and is the variable for resistivity

important fact

Equivalent current, equivalent resistance, and equivalent voltage have to be found before ANY junction values in a circuit.