Thursday, September 8, 2011

Free Fall and Time Dilation

Good Evening PRE-AP-er’s
We have completed Chapter 2 of our textbook. Tonight, we will be discussing free fall and time dilation. You may find information on these topics in section 2-3 in your textbook. Please read the section before joining the discussion. In addition, we are studying for the quiz on tomorrow, which will cover distance, displacement, speed, velocity, and/or acceleration. on tomorrow. Post your questions and one of your classmates or I will assist you.

Here are some things that crossed by mind. Submit your thoughts.

1. Look at picture 2-14 on page 60 and think about this. If the feather and the apple experiment were performed on the moon, where free-fall acceleration is approximately one-sixth the value of free fall acceleration on Earth, how would the picture compare with Figure 2-14?

2. Before Einstein published the special theory of relativity in 1905, physicists struggled with some contradictions in physics. The Principle of Relativity states that the laws of physics are the same in a reference frame. However, it did not allow for the fact that the speed of light is independent of the reference frame from which it was measured in. Read the section and explain in your own words why the passenger on the train (in the discussion page 66-67) measures a shorter time interval.

Here is a question to earn extra credit:
Two stones are thrown from a cliff at the same time with the same speed. One is thrown upward and one downward. Which stone, if either, will hit the ground first? Which stone, if either, will hit the ground with a higher speed? Make your best argument for you prediction. For extra credit on the quiz (10 points), set up an numerical example and solve it to test your predictions. Submit your example on tomorrow before 3pm.

Have a GREAT DISCUSSION!!!!!!!!!!

15 comments:

brittanytoy said...

1)Wouldnt the accelerations be slower than the figure on 2-14, because it would take a longer amount of time to cross the same intervals(also because of gravity issues?)?!

Eva Michelle Zapata said...

I agree with Brittany because if the acceleration is 1/6 of the acceleration on earth then a low amount of acceleration means it would go slower?

Angela said...

First off the objects would fall at the same rate even if they are on the moon.
The passenger has to measure a shorter interval because they can only see the light coming from that particular spot while the observer sees more than just one spot on the train. Well I'm not sure if that's right but that's what i think..

Anonymous said...
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Anonymous said...

I think the passenger on the train measures a shorter time interval because the passenger is moving along with the train. and the person besides the track of the train is moving with respect to the track of the train.

Eva Michelle Zapata said...

Can we submit the exta credit in class on paper?

matthew said...

Because of the lack of gravity technically if you placed both the feather and the apple above the ground on the moon they would both stay in the same place or slightly drift in random directions due to to other variables

Ms. Deborah Wilkes said...

You may submit it any time tomorrow. But I will not discuss the problem until Monday, Sept. 12.

Delaney Walters said...

If you dropped the apple and feather at the same time on the moon in 1/6 gravity, they would just fall 5/6 slower making the air time longer making the graph a less steep slope.

Avery O. said...

It would look the same on a strobe camera, but if you timed the free fall the time should be 6 times longer than on the earth. Besides, 14-3 is wrong because the feather would fall slower than the apple due to its wide surface area and the air resistance caused by the atmosphere. The observer on the train measures a shorter time interval because they are moving with the train, at the same speed the light is moving forward, so they see it go straight up and down.

Malith said...

If Both Items were dropped on the moon the time intervals while both objects are falling would be longer but the objects would still hit the ground at the same time given no resistance.

Cristal_R 2ND PER said...

The objects on the moon would have a slower acceleration because of the lack of gravity, making the displacement changes smaller. The passenger on the train measures a shorter time because he is moving with the train and the light is also moving with him, as where the observer beside the train sees the light at an angle and only for a few moments because the train keeps moving.

Odalis d8D> said...

I agree with Brittany and Michelle because i think that the accelerations would be slower

CaitlinLuper :D said...

I think the accelerations on the moon would be slower as well. Because they have slower accelerations.

cadavkel000 said...

1) given that the objects would both be falling at the same time on the moon, where there is no air resistance, then the objects would take a longer period of time to fall, but would eventually fall at the same time and at a constant acceleration, or "g."