Download - Weight and MASS.ppt
Weight and MASS
What we want to achieve....
• Be able to recall the difference between mass and weight
• Be able to calculate you weight on other planets
• Be able to describe why the value of gravity is different on different planets
Brainstorm, what do we already know about gravity?
Gravity
Newton is famous for his theory of gravity
He actually worked out how the mathematics or the ‘rules or gravity’
The rules of Gravity affect everything that has mass so that meansYou, books, calculators, the planets, stars and teachers.
He is famous for the apple story
Although this probably never happened
All masses are attracted to each other
The force of gravity depends on the distance between the two masses and the Size (magnitude) of the two masses
FORCE is measured in NEWTONS (N)
Gravity pull all objects down at the same rate
Air resistance will slow some object but there is no air on the moon so...
MASS and WEIGHT are NOT the same thing!!!!!!!!!!
x Gravity
Mass is the same wherever you are as it is the amount of stuff (particles) that are in you
Weight is your mass multiplied by the gravitational pull of the planet you are on
Your weight is a force and is measured in Newtons
On Earth your weight is roughly 10x your mass
120kg 1200 N120kg x 10 =
On the moon the gravitational force is 6 time less than on Earth
x Gravity
120kg 200N120kg x 1.6 =
This is because the moon has 1/6 less mass than the Earth it has 1/6 less gravitational pull
The man has lost weight by going to the moon but what about his mass?
Place Weight of 1Kg Calculation Your weight (N)
Earth 10N
Mars 4N
Jupiter 23N
Pluto 3N
Uranus 11N
Venus 9N
Neptune 10.6N
On the moon 0.1N
In deep space 0N
If you know your weight in KG you can use that, otherwise use 50KG as your mass
Copy into your book the table above and calculate your weightRemember weight = mass x gravity
Conclusion-Where in the solar system would you weigh the most? How much would you weigh?Where in the solar system would you weigh the least? How much would you weigh?Trick QuestionWhat would your mass be on the moonWhat would your mass be on Pluto
Watch the video and answer these questions
1)What objects equal roughly 1 Newton?2)What is 1 Newton in Kgs?3)What is the force of gravity measured in?4)What is weight measured in?5)How much does your mass change when you are on the moon?6)Why do you weigh less on the moon? (refer to the mass of the moon)
Video review
Gravity and distanceThe Force of gravity decreases the further you move the two masses apart
The further you move away from the Earth the smaller the gravitational pull you will feel and your weight will go down.
Warning: THERE is gravity in space
Watch this videoOn zero gravity on
Earth
Force from Earth
ForceFromMoon
When will there be no resultant force on the spaceship?
1/6 mass of Earth
Apollo 131
2 3 45
Imagine you are a member of Apollo 13 describe your journey with respect to the gravitational pull of the Earth and moon.