Phys 172 exam 1 formulas

F

F=m*a

Gravitational force

F=G(m1m2/R^2)

Electrostatic force

F=k(q1q2/r^2)

ke=9x10^9 (Coulombs constant)

Spring force

Fs=ks*x

ks=spring constant

x=displacement

Static Frictional force

Ff<=us*N

N=normal force

Kinetic frictional force

Ff=ukN

N=normal force

Buoyant force

FB=Pfluid*Vsubmerged*g

Centripetal force

F=mv^2/r

Momentum

P=mv

P=Fnet*t

Momentum update

Pf=Pi+Fnet*delta t

Conservation of momentum

Psys+Psurroundings=constant

Conservation of momentum

Delta Psys+ delta Psurroundings = 0

Predicting motion step 1

Find Fnet

Fnet=m*a

Predicting motion step 2

Update momentum

Pf=Pi+Fnet* delta t

Predicting motion step 3

Find V avg

Vf=Vi + Fnet/m * delta t

Vf=Pf/m

Predicting motion step 4

Update position

rf=ri+Vavg * delta t

Static

No acceleration

Use... Fnet=0

Dynamics

there is acceleration

use... Fnet=ma

Motion of block on spring

x=x0 *cos(w*t)

x0=initial displacement

w=angular frequency

w=sqrt(ks/m)

ks= spring constant/spring stiffness

Parallel springs total stiffness

Ktotal=(Ks)*number of springs

Series springs total stiffness

Ktotal=ks/number of springs

Young's modulus

Y=stress/strain

Y=(F/A)/(delta L/L)