What we want to achieve.... <ul><li>Be able to recall the difference between mass and weight </li></ul><ul><li>Be able to calculate you weight on other planets </li></ul><ul><li>Be able to describe why the value of gravity is different on different planets </li></ul>
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 means You, 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 N 120kg x 10 =
On the moon the gravitational force is 6 time less than on Earth x Gravity 120kg 200N 120kg 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 ?
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 weight Remember 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 Question What would your mass be on the moon What would your mass be on Pluto 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
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 distance The 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 video On zero gravity on Earth
Force from Earth Force From Moon When will there be no resultant force on the spaceship? 1/6 mass of Earth
Apollo 13 1 2 3 4 5 Imagine you are a member of Apollo 13 describe your journey with respect to the gravitational pull of the Earth and moon.