Potential Energy and Conservation of Energy Formula

Question 1

Relationship of potential energy and work

Answer 1

change in potential enrgy (Uf - Ui) = - Work
change in potential energy = integral f(x) dx

Question 2

Gravitational potential energy

Answer 2

Change in U = mgy = mg(yf - y1)

Question 3

Elastic Potential Energy

Answer 3

U(x) = 1/2 kx^2

Question 4

Mechanical Energy

Answer 4

Emec = KE + U

Question 5

Conservation of Mechanical energy

Answer 5

0 = (Kf - Ki) + (Uf - Ui)
Ki + Ui = Kf + Uf

Question 6

Potential Energy Cruves

Answer 6

F(x) = - d U(x) /dx

Question 7

Work done on a system by an external force (w/out frictional force)

Answer 7

W = Emec = Change in KE + Change in U

Question 8

Work done on a system by an external force (w/ frictional force = Ethermal energy)

Answer 8

W = Emec + Eth
E thermal energy = force of kinetic friction (d)

Question 9

Total energy E of a system

Answer 9

Work = Total Energy = change in Emec + change in Eth + change in internal energy (Eint)

Question 10

Average Power

Answer 10

Pavg = change in Energy/change in time

Question 11

instantaneous power

Answer 11

P = dE/dt