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Goal: To begin to understand how Newton used theory to further the fields of physics and astronomy. Objectives: 1)To learn about the overview of what Newton.

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Presentation on theme: "Goal: To begin to understand how Newton used theory to further the fields of physics and astronomy. Objectives: 1)To learn about the overview of what Newton."— Presentation transcript:

1 Goal: To begin to understand how Newton used theory to further the fields of physics and astronomy. Objectives: 1)To learn about the overview of what Newton did in his career 2)To learn about inertia

2 First, a question we will come back to every week for this first month Batman is trapped by the joker in the center of a frozen lake. The ice of this lake has no friction. It turns out with no friction you cannot walk/run How will batman save himself? Stay tuned…

3 Isaac Newton (1642-1727) Newton was the father of theoretical physics! Had some mathematical discoveries such as calculus. Created “classical mechanics” – branch of physics. Used a prism to prove that white light was actually a combination of many colors of light – lead to his book on optics. Came up with his 3 laws of motion.

4 Newton’s Laws: Law 1: Law of Inertia (Inertia means ability to resist change) A body in rest stays at rest until acted upon by an outside force, and a body in motionremains in motion until acted upon by an outside force.

5 What is “force”? Force is just the pushing or pulling on something. If you push on a door, that is a force on the door and by Newton’s first law, that door now has to change its motion (none) to a new motion (opening).

6 Concepts question You are in the center of a frozen lake which has no friction and is completely smooth and flat. Ignore wind resistance. You toss out a hockey puck at a speed of 1 mile per hour. How fast does the hockey puck go when it is close to the edge of the lake (assume the lake is 500 miles across)?

7 More concepts You are in a space craft which is over a trillion miles from the closest star (so that means there is very little gravity on you) traveling at a speed of 2 miles per second. If you run out of “gas” so to speak, what will happen to your spacecraft and why? How far do you think you will go before you stop?

8 Weight One form of force is called “weight”. Weight is your total downwards force. In this case it is the earth pulling you down. Units of weight can be pounds or Newtons. Note that while your mass is the same anywhere you go, your weight is not. One way to loose weight without loosing any mass is to move to the equator. Since the earth spins there is an outward force – and this decreases your net downward force, which decreases your weight.

9 Moon weight The moon has 1/6 th the gravity of the earth. If you weighed 180 lbs on earth then how much would you weigh on the moon? If your mass on earth was 80 kg then what is your mass on the moon?

10 How do you move something? Well, you apply a force. This force makes it accelerate. The stronger the force, the faster it accelerates. If an object is at rest, and you give it a force in the North direction, what direction will it move? If an object is moving North and you give it a force in the South direction and keep applying that force for a long time then what will happen to the object?

11 Now for a tricky one I toss a ball in the North direction (giving it a force in that direction). Gravity pulls down on the ball. What will the motion of the ball be like?

12 Equilibrium Note: net force is the sum of all forces. To add up forces they have to point in the same direction. Note that up = -down I stand on the ground. What is the net force on me (hint, is my velocity changing)?

13 What force? Gravity is pulling down on me with a force of about 1000 N. What pushes me upwards with a force of 1000 N and what would happen if this force suddenly went away?

14 Run away supertanker A supertanker has its engines locked in the on position but is headed for harbor. The supertanker’s engines proved force such that there is a forwards force of 1 million Newtons Ten tugboats tie themselves to the supertanker and push their engines to the max (100,000 Newtons) in the opposite direction. What is the net force on the supertanker? Will the supertanker stop before it runs into the shore? We will ignore air and water resistance for this question.

15 Conclusion We have learned that unless an object is pushed or pulled on, it will keep moving at a constant speed (and if that speed is 0, it stays put). So, for Batman to get off the frozen lake, he needs a force – but where oh where can he get that force from? Is Batman doomed to stay on that lake forever? Stay tuned….


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