Topic A

Ideas

o        If m1=m2 and moving 1 collides with stationary 2, then v1=0, v2=u1 i.e. the second ball moves off with the original velocity of the first and the first remains stationary

o        If m1<<m2 and minute mass 1 collides with massive stationary mass 2 then v1»-u1 and v2»0

o        If m1>>m2 and massive mass 1 collides with stationary minute mass 2 then v1»-u1 u1 and v2»2u1

Equations

 

Recall and use:

ü         E= ½mv2                Kinetic Energy = ½ x mass x (velocity)2

ü         E=mgDh                Potential Energy = mass x g x height change

·         v=Ö(2gh)

ü         W=Fd                    Work done = force applied x distance moved in direction of force

·         Efficiency = (useful energy out)/(total energy in)

ü         P = Fv                   Rate of transfer (power) = force applied x velocity (if F & v constant)

·         P=dW/dt

ü         FDt=Dmv              Impulse = change in momentum OR force = rate of change of momentum

·         F=dp/dt

ü         F=ma                    Force = mass x acceleration for constant mass

ü         pV=nRT                 pressure a 1/volume (n=moles, R=molar gas constant, T=temp)

ü         Fmax = mN               Limiting value of frictional force = coefficient of friction x normal reaction force

 

Use (given on formula sheet):

Ø              F = kx

Ø              stress = tension/cross-sectional area

Ø              strain = extension/original length

Ø              Young modulus = stress/strain

Ø              g = Fl/Ax

Ø              elastic strain energy = ½ kx2

Ø              elastic strain energy per unit volume = ½ stress x strain

Ø              pV=1/3Nmc2          pressure x volume = 1/3 particles x mass of 1 particle x (average velocity)2

Ø              p = 1/3 rc2            pressure p, density r, average velocity squared c2

Ø              mean kinetic energy