WEP

Question 1

Defn of energy

Answer 1

Energy is the capacity to do work

Question 2

GPE aka … & eqn

Answer 2

aka WD against gravity = mgh

Question 3

Eqn for elastic potential energy

Answer 3

1/2 kx^2

Question 4

Eqn for KE

Answer 4

1/2 mv^2

Question 5

Power eqn

Answer 5

P = dw / dt = d (Fs) / dt = F ds / dt = Fv

Question 6

Efficiency eqn

Answer 6

n = Pout / Pin X 100% = Eout / Ein X 100%

Question 7

Principle of COE - eqn

Answer 7

Total Ei = Total Ef

KEi + GPEi + EPEi + Wforce (any force) = KEf + GPEf + EPEf + Wfriction

Question 8

How to draw the E - s graph for EPE, GPE & KE

Answer 8

GPE is linear
EPE is exponential
KE = sad face

Question 9

Try speed boat eg in notes

Answer 9

Total P = Fv = kv^2 . v = kv^3
24000 X 3 = k (12)^3 
k = 41.67
Next, when only 2 engines are working
24000 X 2 = 41.6 v^3
v = 10.5 m/s

Question 10

How to find wk done from 2 graphs

Answer 10

Are under
F - s graph &
P - V graph