Newton’s 3 Laws of Physics

An object tends to stay at rest and an object tends to stay in motion (in a straight line at the same speed) unless some outside force acts on the object.

Review

Inertia is the tendency of an object to resist changes in its state of motion. But what is meant by the phrase state of motion?

Inertia: tendency of an object to resist changes in its velocity. The state of motion of an object is defined by its velocity - the speed with a direction. Thus, inertia could be redefined as follows: Inertia: tendency of an object to resist changes in its velocity.

Weight and Mass

 Suppose that you filled a baking dish to the rim with water and walked around an oval track making an attempt to complete a lap in the least amount of time. The water would have a tendency to spill from the container during specific locations on the track. In general the water spilled when: the container was at rest and you attempted to move it the container was in motion and you attempted to stop it the container was moving in one direction and you attempted to change its direction.

The water spills whenever the state of motion of the container is changed. The water resisted this change in its own state of motion. The water tended to "keep on doing what it was doing." The container was moved from rest to a high speed at the starting line; the water remained at rest and spilled onto the table. The container was stopped near the finish line; the water kept moving and spilled over container's leading edge. The container was forced to move in a different direction to make it around a curve; the water kept moving in the same direction and spilled over its edge. The behavior of the water during the lap around the track can be explained by Newton's first law of motion

Try This Acquire a metal coat hanger for which you have permission to destroy. Pull the coat hanger apart. Using duct tape, attach two tennis balls to opposite ends of the coat hanger as shown in the diagram at the right. Bend the hanger so that there is a flat part that balances on the head of a person. The ends of the hanger with the tennis balls should hang low (below the balancing point). Place the hanger on your head and balance it. Then quickly spin in a circle. What do the tennis balls do?

An EXPERIMENT to try.

Demo #2 Demo #1 Demo #3

Your Turn Design your own experiments that would demonstrate Newton’s first law. An object at rest likes to stay at rest, and an object that is in motion likes to stay in motion, unless a force acts on the object. Follow the Experimental Write Up process to complete this physics lab. See next page!

Title Purpose Materials Method Hypothesis Observations Conclusion Catchy Inertia Title Why are we shooting this video? List Everything Needed (For Every Scene) Procedure of every demonstration Make it happen! Record your observations Video each demonstration Did your video teach “Newton’s First Law of Motion”

CAMERA SHOTS AND MOVEMENTS

WIDE Shots Extreme Widest focal length Used to set the Atmosphere of the scene. 3 or 4 seconds is a good time.

Medium Shots Waist Shots Medium Close-ups Shows a portion of the background but the image should be close enough to keep our attention. Great for showing the location of the shot, but close enough to reveal the details of the action.

Close-up Shots Caution Details are magnified. Objects can look bigger than they really are.

Close-ups Extreme

Camera Movements

Storyboard

Find 5 other objects to weigh. Calculate the amount of force needed to hold up each object in newtons (N) Remember holding up 100 g = 1 N (newton)

Calculate how many newton’s of force are needed to support your weight.

Galileo Galilei was a physicist, astronomer, mathematician, creative thinking mastermind who lived in the 16thand 17th centuries in Italy. He was the inventor of the telescope, and one of the first people to suggest that the Earth traveled around the Sun and not the other way around. He was very interested in physics and how things worked on Earth, and he conducted a lot of experiments to observe gravity and natural phenomena, quite some time before they were mathematically described by Sir Isaac Newton.

Galileo and many of his contemporaries are thought to have begun experimenting with falling objects and testing the idea that even though objects have different masses, they will fall towards the Earth at the same velocity. Because timing and other factories like wind resistance are an issue at great heights (like dropping a ball from the height of a building), Galileo and fellow scientists used inclined planes, like ramps, to conduct their experiments. Galileo stated that objects in a vacuum, meaning no air, would fall to the Earth with a constant acceleration. Today, we call this constant acceleration gravity.

Acceleration Experiment We need all of this x2

Variables ? We Need to Talk

Title Purpose Materials Method Hypothesis Observations Conclusion Catchy What’s Your Question? List Everything Needed List all the steps What’s supposed to happen? Record your observations You may want to video your experiment! What was your discovery? Was your hypothesis right?

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Check Your Understanding Lets Review

Think of 3 action/ reaction demonstrations. Explain the physics surrounding the demonstrations chosen. Demo # -1 illustrate Explain Demo #2 -illustrate Explain Demo #3 - illustrate Explain

verses

Now It’s Your Turn! One Simple Task. 10 Connected Machines. To do this

Plan Logical layout, neatness, 10 steps clearly illustrated 0 Plan Logical layout, neatness, 10 steps clearly illustrated 0 5 6 7 8 9 10 Creativity 10 unique steps demonstrated, 0 5 6 7 8 9 10 Video Presentation Executed without additional help to press the easy button 1 2 3 4 5 OVERALL MARK /25   A B C+ C C- Incomplete G S N  

Just Press it

Can we prove that Galileo was right acceleration is a constant Can we prove that Galileo was right acceleration is a constant. Around 10 m/s2 Materials 3 feet of molding (for a ceiling or floor, with a groove to roll a ball down) Books to stack Meter stick or ruler Protractor Golf ball Stopwatch Notebook and pen/pencil

Procedure Stack some books and set one side of the molding on the books to create a ramp. Use the protractor to measure the angle between the ramp and the floor. Adjust the stack of books until you can get the ramp as close to 30° as possible. Record the final angle in your notebook. Use the ruler or meter stick to mark 10 cm intervals along the ramp, starting at the floor and going upward. Set the golf ball at a measured distance along the ramp. Time how long it takes for the golf ball to hit the floor after your let the ball go. Record both the distance you let the ball go and the time it takes for the ball to travel the length of the ramp. Repeat step for at different lengths along the ramp. Graph your results. Put time on the x-axis, and distance traveled on the y-axis. Do you notice any patterns? Calculate the acceleration for the points you tested using the equation​ a = 2d / t2

Gravity Lab: Create a title for your lab:_____________________ This experiment had some potential for errors; discuss where these errors could have occurred. ________________________________________________________________________________________________________________________________________________________________________

What strategies did your group use to make this lab a success. ________________________________________________________________________________________________________________________________________________________________________________ After calculating the gravitational acceleration of the golf ball explain how it confirmed or denied that objects accelerate to the earth at a constant acceleration? ________________________________________________________________________________________

Distance (cm) TIME (Seconds) Average Time (sec) Gravity ACCELERATION A = 2d/t x t Trial #1 Trial #2 Trial #3 Trial #4 50 cm 60 cm 70 cm 80 cm 90 cm 100 cm 110 cm 120 cm 130 cm 140 cm 150 cm

Results The acceleration at each point should be almost the same. Differences can be connected to imperfections in timing and friction on the ramp. Why? The graph you create will show that the longer the ball is on the ramp, the faster it will move. With constant acceleration, the velocity of an object will get increasingly faster. The constant acceleration in the experiment is due to gravity. Acceleration due to gravity is measured as 9.81 m/s2. You will not measure this acceleration because of the inclined plane, but if you were to conduct an experiment by dropping balls from different heights, this is what you would expect. If you change the angle of the ramp to be steeper, the acceleration you record will be closer to that of gravity.

What do you think about Galileo Galilei now after conducting this experiment? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Graph the data Acceleration (m/s/s) Distance (meters)