Journal 12/4

1. Explain what part of your original work made me think that you did NOT show understanding of Newton's second law: acceleration of an object is proportional to the net force exerted on the object by other objects, and inversely proportional to the mass of the object. the reason you thought i did not show understanding of newton's second law is because, i originally thought that if you doubled the mass you would also double the speed at which it falls. Which is doesn't.

1. Write a mathematical expression for the force that the earth exerts on an object of mass m. Remember that when an object is falling freely Fnet = Fearth on obj

Fnet= mass (9.8 m/s/s)

2. Your friend Abe says "If you drop a marble and a bowling ball from the top of the school, being careful to let go of them both at the same time, they will both hit the ground at the same instant. This means the force of the earth is the same on both objects." Do you agree with Abe? Why or why not? If you disagree, how would you try to convince him using a real-world example that he could try himself?

The force of the earth is not the same on both of the objects. A marble has a different mass than a bowling ball. While both will hit the ground at the same time, the force of the earth on the bowling ball is greater than the force of the earth on the marble. This is due to the fact that the force of the Earth on any object is equal to the mass times the 9.8 constant. If you drop two weights, they fall at the same time, and land together, but the force is much greater on the one weight with more mass. The more mass an object has, the more force the earth exerts on it.

3. Your friend Ben says "If I duct-tape two bricks together the earth pulls on them twice as hard as a single brick. Therefore, the double brick will fall twice as fast." Do you agree with Ben? Why or why not? If you disagree, how would you try to convince him using a real-world example that he could try himself?

Ben is partially true. If you tape two bricks together, then they the earth will pull on them twice as much because you are doubling the mass of the object. However it will not fall any faster because all things fall at the same speed. You can see this because when you drop two objects with two different masses, they land at the same time.

2. Answer the original questions carefully now that you understand the lesson.

3. What activity, experiment, or lesson helped you to understand this lesson better? The video really helped me to understand the lesson.