10/15 Physics update and homework due 10/22

Hi folks,

Today we spent a bit more time on some more of the interesting aspects of gravity that I hadn't had a chance to cover yet. We also took a step forward into projectile motion and two dimensional motion. I introduced the first of several types of problems that we will be working with over the next few weeks.

Homework for next week is to do the following questions.

1. Whoops, you dropped your cell phone. Well…might as well do some physics.

a. If your cell phone dropped of a 10 m (30 ft) tall building how long will it take before it hits the ground?

b. What speed will your cell phone hit the ground at?

c. What average speed will your cell phone have during the fall?

d. What is the acceleration for your cell phone?

e. Create a velocity vs. time graph for your cell phone.

f. Create an acceleration vs. time graph for your cell phone.


2. Grrr, it turns out you didn't just drop the phone, you really wanted to get rid of it to get another one. But, the darn thing didn't break. So, if at first you don't succeed…

a. You climb to the top of a 27 m water tower (don't do this at home) and you're about to drop it again, but you notice that there several people wandering around down below. Curses! However, there's a pond about 60 m away. Can you throw that far? What horizontal speed would you have to throw the phone at to get it into the pond?

b. What vertical speed will the phone be traveling at when it hits the pond?

c. What vertical acceleration does the phone have after you throw it?

d. What horizontal acceleration does the phone have after you throw it?

e. Draw a graph that represents the vertical acceleration.

f. Draw a graph that represents the horizontal acceleration.

g. Draw a graph that represents the vertical speed.

h. Draw a graph that represents the horizontal speed.