Work and Energy

W =

F||d or Fd(cos) or ΔE

K =

1/2mv²

U_{g =}

mgh. The higher the object is lifted, the greater the gravitational potential energy of the object + earth system.

P =

w/t = Fv (in Watts)

Conservation of EnergyK_{i}+U_{i}+W_{o\operatorname{th}er}=K_{f}+U_{f}

energy before = energy after when no external forces.

energy

the ability to do work (J)

work

the ability to transfer energy (J)

mechanical energy

energy of objects that are moving/can move. KE, PE, IE

potential energy

energy based on position, could be referencing a point or an object

internal energy

thermal. friction.

U_{s =}

1/2kx²

k

spring constant. how hard is it to stretch/compress the spring? more of a coefficient

x

how far from equilibrium it is moved

Hooke’s Law

F_s = -kx. force needed to stretch/compress a spring is proportional to its displacement from equilibrium.

Energy can be transferred into or out of a system in two basic ways:

• Work: transfer of energy by mechanical forces

• Heat: nonmechanical transfer of energy from hotter to colder object

Perfectly elastic collisions

both mechanical energy and momentum are conserved.