Mass vs. Weight

Questions• Are some objects harder to get to start moving than others?

• Are some objects harder to slow down than others?

WHY???

Mass vs. Weight• Mass• The amount of matter an object is made up of• Measure of an object’s resistance to motion (inertia)• Measured using a balance

• Weight• The pull of gravity on an object• Is a force units = Newtons• Measured using a scale

Mass vs. Weight• As gravitational fields change…• Does an object’s mass change?• Does an object’s weight change?

• As gravitational force increases, an object’s…• Weight ______• Mass ______

Calculating Weight• Equation• W = mg

• W = weight• m = mass• g = constant

• Earth constant -

Calculating Weight• Equation• W = m x g

• W = weight• m = mass• g = constant

• Earth constant - 0.01 N/g

- 10 N/kg• Moon constant -

Calculating Weight• Equation• W = m x k

• W = weight• m = mass• k = constant

• Earth constant - 0.01 N/g

- 10 N/kg• Moon constant - 0.0017 N/g

- 1.7 N/kg

Eureka – Weight vs. Mass• https://www.youtube.com/watch?v=xfGll1REu2A

Questions

1. What is the weight on Earth of a 30 kg dog?2. How much does a 200 kg boulder weigh on the moon?3. How much force is applied to 100 g on Earth?4. What is the mass in kg of a 100 N car on Earth?5. A 4 kg rock has a weight of 20 N on a random planet. What

is that planet’s grav. constant?

Questions

1. If your mass is 100,000 g, what would you weigh on Earth? On the moon?

2. A gorilla has a weight of 250 N on Earth. What is its mass in kg on the moon?

3. If you have a mass of 400 kg and the force of gravity on you is 80 N, what is the gravitational constant for the planet that you are on?

4. If your weight on the moon is 100 N, what is your weight on Earth?

Questions

1. How much mass in kg does a 17 N boulder on the moon possess?

2. If your weight on the moon is 50 N, what is your mass in grams on Earth?

3. What is the gravitational constant of the planet BOOMBOOM if a 300 kg hippo has a weight of 900 N?

Questions

1. If your pet tortoise Toodles weighs 150 N on Earth, what is Toodles’ mass in kg on the moon?

2. A 4 kg rock has a weight of 20 N on a random planet. What is that planet’s grav. constant?