Work
W = Fdcostheta
Normal force, centripetal force, and magnetic force do not exert
work since they are always perpendicular to the motion
Energy is path independent, helps simplify kinematics equati
Mechanics II
Center of mass: where mass forces are balanced
Not necessarily within the object
Xcm = X1m1 + X2m2 + X3m3 / m1 + m2 + m3
When dealing with a stick, assume a third mass in the middle whic
Mechanics I
Force
Push or pull on an object
Netwons 1st Law: Object in motion stays in motion, while an object at rest
stays at rest
F = 0, a = 0
Newtons 2nd Law: a = Fnet/m
Inertia: Resistance to
Hour Exam 2, PHY 2140 answer sheet
FORM A
10/23/12
Name (for your information only) _
During Exam:
Closed book, closed notes, no talking, no cell-phone use
Baseball caps or other brimmed hats worn wit
Electric Charge
Electric charge is either positive or negative
e = Elementary charge = 1.6E-19 C
Charge of electron and proton
Total charge of something must be multiple of elementary charge = n(+/e)
Inclined Planes
Uncouples the normal force and gravity
Force along incline (Horizontal) is mgsintheta
Force perpendicular (Vertical) is mgcostheta
Force along incline = 0
Rope
Uniform tension when it
Fluids
Gas or liquid
Has a uniform density to allow to find mass
p = m/v
Can store energy as pressure
Specific Gravity: Density of something compared to density of water
= density of substance/density
Conductors, Insulators, and Polarization
Conductor: Contains charges free to roam throughout the material
Any net charge on a conductor resides on the objects surface
Therefore no electric field insid