10/9 MS Physics update and homework due 10/16

Hi folks,

Today we introduced the concept of gravity to everyone. We explored the concept that gravity accelerates everything at the same rate.  Next week we will dive even deeper into gravity.

Just in case you want to show/explain the "Monkey and the Tree" problem to someone, here's the video we saw in class.

For homework this week, please do the following questions that are all based on today's lecture.  If you don't remember the answer, please check your notes and if it's not in your notes feel free to watch the recording. 

Answers are included so that you can be sure you have the right answers for next week's quiz. 

1.  What kinds of things have a gravitational pull?

2.   If a heavy ball and a light ball are both dropped at the same time, which one hits the ground first?

3.  In the video with the bowling ball and the feathers, why did the feathers fall slower than the ball the first time and faster than the ball the second time?

4.  In the thought problem with the gun shooting one bullet very fast while, at the same time, another bullet just drops from the gun, which bullet hits the ground first?

5.  Explain your answer for #4, why does what you said happen?

6.  So, the wildlife biologist aims the tranquilizer dart gun directly at the monkey.  If the monkey lets go of the tree when the biologist fires, does the dart hit the monkey?

7.  Let's try this monkey tree thing again, but this time, what if we could do it in such a way that there is no gravity.  Now what happens to the dart and the monkey?  Does the dart hit the monkey now?

8.  Is there gravity on the Moon?

9.  What does gravity have to do with acceleration?

10. Give me an example of gravity causing something to speed up?

11.  Give me an example of gravity causing something to slow down?

ANSWERS

1.   All things have a gravitational pull.  However, something has to be VERY big before it really can be felt.

2.  Trick question!  Neither hits the ground first.  Gravity accelerates everything evenly so both balls will hit the ground at the same time?

3.  The first time there was air in the chamber so there was normal air resistance.  The second time all the air was removed so the feathers fell just as fast as the ball.

4.  Trick question!  They both hit at the same time…again!  

5.  Because gravity doesn't care.  Gravity will accelerate EVERYTHING downward at the same rate whether it's moving or just falling straight down.

6.  Yup.  Gravity will pull everything down at the same rate of speed.

7. Yup.  In this case the dart will just keep going in the direction it was shot.  It won't be pulled down by gravity.  Also, the monkey can let go of the tree but since there's no gravity, it will just sit there.  It won't be pulled down.  So the dart will hit the monkey again.  Poor monkey. :(

8.  Yes, not as much as on Earth but there is still gravity on the Moon.

9.  Gravity causes things to speed up or slow down.

10.  Bunches of answers here but for example, a roller coaster zipping down the hill picking up speed as it goes.

11.  Again, a lot of answers here but an example would be throwing a ball into the air.  From the moment you throw it it begins to slow down until it stops and turns around in mid-air.