Warm Up 1.What are units for velocity? 2.What are units for acceleration? 3.What is the equation for acceleration? 4.What is the equation for velocity?

Objective I CAN: –Relate gravitational force to mass and distance

Gravitational Force The force of attraction between all masses in the universe

Very Important!! Responsible for: –Creation of black holes –Structure of galaxies –Expansion of the universe –Things falling to the ground –Humans only being able to jump so high

Gravity affects everything! Universal Gravitation

Gravity affects everything! Universal Gravitation

Gravity affects everything! Universal Gravitation

Gravity affects everything! Universal Gravitation

Newton’s Law of Universal Gravitation: F g = G m 1 m 2 r 2 Universal Gravitation ( )

F g = G m 1 m 2 r 2 F g = Gravitational Force G = Constant = 6.7 x m 1 = mass 1 m 2 = mass 2 r = dist b/w center of the 2 Universal Gravitation

Gravitational constant is CONSTANT (does not change) Mass- kg Distance- m Force- newtons (N) because that’s what happens when you discover things

Newton’s Universal Law of Gravitation Gravitational force- weakest of all forces How does it hold the planets in orbit???? The planets are VERY large and VERY far apart

What could explain an increase in gravitational force? Fg = G m1m2 r 2

What could explain a decrease in gravitational force? Fg = G m1m2 r 2

Effect of gravitational force ↑ mass causes ↑ Fg ↓ mass causes ↓ Fg ↑ distance causes ↓ Fg ↓ distance causes ↑ Fg …but by how much???

If the mass is multiplied by some number, then Fg is multiplied by that number If the mass is divided by some number, then Fg is divided by that number

What happens to gravitational force if the mass of one object is multiplied by 2? Fg = G m1m2 r 2

What happens to the gravitational force if the mass of both bodies is multiplied by 2? Fg = G m1m2 r 2

What happens to gravitational force if the mass of both objects is multiplied by 3? Fg = G m1m2 r 2

What happens to the gravitational force if the mass of one body is multiplied by 3 and the mass of the other body is multiplied by 1/2? Fg = G m1m2 r 2

If the distance is multiplied by some number, Fg is divided by the SQUARE of that number If the distance is divided by some number, Fg is multiplied by the SQUARE of that number

What happens to the gravitational force if the distance between the objects is multiplied by 2? Fg = G m1m2 r 2

What happens to the gravitational force if the distance between two objects is divided by 2? Fg = G m1m2 r 2

What happens to the gravitational force if the distance between two bodies is multiplied by 3? Fg = G m1m2 r 2

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How to calculate? Multiply out m1xm2/r 2 Multiply that times 6.7 Remember scientific notation? Want one number in front of decimal If move decimal left, exponent becomes less negative If move decimal right, exponent becomes more negative

If two.08kg cheerios are.03m apart, what is the gravitational force between them? Universal Gravitation

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 Universal Gravitation

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 Universal Gravitation

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = (6.7 x )(.08 x.08) (.03) 2 Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = (6.7 x )(.0064) (.03) 2 Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = (6.7 x )(.0064) (.0009) Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = (6.7)x( )x(7.1) Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = (6.7x7.1)x( ) Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = (48)x( ) N Universal Gravitation F g = G m 1 m 2 r 2

If two.08kg cheerios are.03m apart, what is the gravitational force between them? m 1 =.08 m 2 =.08 r =.03 F g = 4.8 x N Universal Gravitation F g = G m 1 m 2 r 2

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Cool Down 1.Does the gravitational constant ever change? 2.How does gravitational force change is distance is tripled? 3.How does gravitational force change if the mass of both bodies is doubled? 4.HW: finish worksheet