Mass vs Weight

Mass Amount of matter in an object Does NOT change with location Measured in grams with a balance

Weight The force of gravity on an object DOES change with location Measured in Newtons with a scale Weight = mass x gravity Fw = mg gearth = 9.8 m/s2 (mass must be in kg) gmoon = 1.6 m/s2 gJupiter = 24.8 m/s2

Practice Problems Your cat has a mass of 2kg. What is her weight in Newtons on Earth? Fw = mg Fw = 2kg x 9.8 m/s2 Fw = 19.6 N

2. What is your cat’s weight on the moon? (g = 1.6 m/s2) Fw = mg Fw = 2kg x 1.6 m/s2 Fw = 3.2 N

3. What is your cat’s weight on Jupiter? gJupiter = 24.8 m/s2 Fw = mg Fw = 2kg x 24.8 m/s2 Fw =49.6 N Same size, same amount of stuff (mass), but different gravity

Gravity Force that acts between any two masses, an attractive force that pulls objects together