1. Including friction and gravity
Weight vs. Mass
Including friction and gravity

2. Friction Friction is a force that opposes (goes against) motion.
Ex. – tires on the road, sledding, rubbing your hands together.
Friction

3. Gravity is an attractive force between objects that have mass.

4. Weight vs. mass Force due to gravity. S.I. unit = N
Depends on location
Changes based upon gravity
g = w; g = w
acc. due to g = 9.8 m/s2 (on Earth)
w = mass x gravity
w = mg
Amt. of matter in an object.
S.I. unit = g
Does not depend on location
If m increases, w increases
If w increases, m may or may not increase (g Δ’s)
Weight vs. mass