Work
W=Fdcosθ[M1L2T−2] [SI: J]
W=F⋅d[M1L2T−2] [SI: J]
W=∫x1x2F(x)dx[M1L2T−2] [SI: J]
Kinetic Energy
KE=21mv2[M1L2T−2] [SI: J]
KE=2mp2[M1L2T−2] [SI: J]
Potential Energy
PEg=mgh[M1L2T−2] [SI: J]
PEs=21kx2[M1L2T−2] [SI: J]
Work-Energy Theorem
Wnet=ΔKE=21mvf2−21mvi2[M1L2T−2] [SI: J]
Energy Conservation
KE+PE=E=constant (no non-conservative forces)[M1L2T−2] [SI: J]
ΔEmech=Wfriction=−fkd[M1L2T−2] [SI: J]
Power
P=tW[M1L2T−3] [SI: W]
P=Fvcosθ[M1L2T−3] [SI: W]
P=F⋅v[M1L2T−3] [SI: W]
1 hp=746 W
1 kWh=3.6×106 J [SI: J]
Vertical Circular Motion (String)
vtop,min=gR[L1T−1] [SI: m/s]
vbottom,min=5gR[L1T−1] [SI: m/s]
vside,min=3gR[L1T−1] [SI: m/s]
Tbottom=Rmv2+mg[M1L1T−2] [SI: N]
Ttop=Rmv2−mg[M1L1T−2] [SI: N]
Tbottom−Ttop=6mg[M1L1T−2] [SI: N]
vb2−vt2=4gR[L2T−2] [SI: m2/s2]
Vertical Circular Motion (Rod)
vtop,min=0[SI: m/s]
vbottom,min=4gR=2gR[L1T−1] [SI: m/s]
Elastic Collision
v1=m1+m2(m1−m2)u1+2m2u2[L1T−1] [SI: m/s]
v2=m1+m2(m2−m1)u2+2m1u1[L1T−1] [SI: m/s]
e=u1−u2v2−v1=1(elastic)
Perfectly Inelastic Collision
vf=m1+m2m1u1+m2u2[L1T−1] [SI: m/s]
ΔKEloss=2(m1+m2)m1m2(u1−u2)2=21μurel2[M1L2T−2] [SI: J]
e=0(perfectly inelastic)
Bouncing Ball
e=Hh(dimensionless)
where H = drop height, h = bounce height.
Spring Constant
k=xF[M1L0T−2] [SI: N/m]