U1 Equations

Question 1

Momentum

Answer 1

p =mv

Question 2

Linear momentum (before and after a collision)

Answer 2

Total initial momentum = total final momentum
ma ua + mb ub = ma va + mb vb

Question 3

Explosions

Answer 3

-ma va = mb vb

Question 4

Impulse (momentum)

Answer 4

Delta p = f x t

f = mv - mu /t

Question 5

Momentum of objects that combine

Answer 5

ma ua + mb ub = (ma + mb)v

Question 6

Work

Answer 6

W = f s

Question 7

GPE

Answer 7

GPE = mgh

Question 8

Mechanical energy

Answer 8

GPE + ke

Question 9

Work done (with ke of object before and after)

Answer 9

f s = 0.5 m v^2 - 0.5 m u^2

Question 10

Power (energy and force equations)

Answer 10

P = e/t
P =f v

Question 11

Current

Answer 11

Q =It

Question 12

Voltage (energy) (power)

Answer 12

V = E/Q
P =IV

Question 13

Charge (electrons)

Answer 13

Q = ne

e = 1.6 x10^-19

Question 14

Resistance (voltage) (power)

Answer 14

V = IR
P = I^2R

Question 15

Resistivity

Answer 15

R = pL/A

p = Resistivity
R = resistance
L = length of material (usually 1m)
A =area of material

Question 16

EMF

Answer 16

EMF = V + Ir

V= pd
Ir = lost volts

Question 17

Vout in potential divider circut

Answer 17

Vout = R1 x Vin / Total R