Energy and Efficiency

Question 1

Ep = mgh

Answer 1

Ep = Potential Energy (J)
m = mass (kg)
g = gravity 9.8ms⁻²
h = height (m)

Question 2

Ek = 1/2mv^2

Answer 2

Ek = Kinetic Energy (J)
m = mass (kg)
v = velocity (ms-1)

Question 3

Eh = cmΔT

Answer 3

Eh = Heat Energy (J)
c = specific heat capacity (J kg-1 K-1)
T = Temperature (K)

Question 4

Ew = Fd

Answer 4

Ew = Work done (J)
F = Force (N)
d = distance (m)

Question 5

P = E/t

Answer 5

P = Power (W)
E = Energy (J)
t = time (s)

Question 6

P = IV 
P = V^2/R 
P = I^2R

Answer 6

P = Power (W)
V = Voltage (V)
R = Resistance (Ω)

Question 7

Ee = VIt

Answer 7

Ee = Electrical Energy (J)
V = Voltage (V)
I = Current (A)
t = time (s)

Question 8

P = Fv

Answer 8

P = Power (W)
F = Force (N)
v = velocity (ms-1)

Question 9

P = 2πnT

Answer 9

P = Power (W)
n = revolutions per second 
T = Torque (Nm)

Question 10

ƞ = Energyₒᵤₜ/Energyᵢₙ

Answer 10

ƞ must be written as a percentage.

Question 11

ƞ = Powerₒᵤₜ/Powerᵢₙ

Answer 11

ƞ must be written as a percentage.