Equilibrium, Torque, and Energy

Question 1

equilibrium

Answer 1

no translational or angular acceleration

sum of all forces acting on system equals zero

Question 2

static equilibrium

Answer 2

all velocities are zero

Question 3

dynamic equilibrium

Answer 3

velocities are nonzero but constant

Question 4

torque =

Answer 4

Frsin(theta)
theta = angle between F and r

with lever arm: torque = Fl

Question 5

joule

Answer 5

unit of energy

kg m^2/s^2 or Nm

Question 6

gravitational potential energy =

Answer 6

mgh

Question 7

elastic potential energy =

Answer 7

1/2k delta(x)^2

Question 8

work =

Answer 8

Fd cos(theta) = word done by any force except friction
= energy transferred into a system

Question 9

conservative force

Answer 9

if a force acts on a system as the system moves from point A to point B and back, the total work done by the force is zero
energy change is the same, regardless of the path taken by the system

Question 10

conservative forces don’t do ___

Answer 10

work

Question 11

conservative forces include…

Answer 11

Gravitational forces, Hooke’s law forces, electric and magnetic field forces

Question 12

watt

Answer 12

J/s, rate of energy transfer

delta(E)/t

Question 13

instantaneous power due to a force =

Answer 13

Fv cos(theta)