Ex 1)
An object slides across a horizontal table which changes its KE from 20 J to
18 J in 2 sec. What work does the object do against friction?
Ex 1) An object slides across a horizontal table
which changes its kinetic energy from 20 J
to 18 J in 2
sec. What work does the object
do against friction?
Wf = 2 J
**Work against friction increases
an object's Internal Energy** (makes it hotter)
Friction is a nonconservative force
(doesn't store energy)
(can't get back)
Joule Paddle
Conservation of Energy
Harper's New Monthly Magazine, No. 231, August, 1869.