Homework Due Friday Feb 18

1) Riya asked a question on Tuesday - why do all objects fall at the same rate on earth if greater mass of an object means smaller acceleration of the object?  I gave a wrong answer by saying that "technically" the lighter object accelerates slightly faster than the heavier object but that the difference is so small that we don't notice it.  What was wrong with my answer?  It is a fact that a heavy object and a light object dropped from the same height will accelerate at EXACTLY the same rate.

HINT: look at Newton's law of gravitation GmM/(r^2).  Consider a small object of mass m and a big object of mass M dropped from a given height on the surface of the earth.  What will be the force acting on each object?  What will be the acceleration of each object?  Remember to set the force of gravity equal to m*a.

2) Find out what the following "stuff" (the elements, compounds etc.) is made of by searching online
- living beings
- the crust of the earth
- the air we breathe
- the sun
-a thing of your choice (can be a natural or man-made object)

3) Find a current news or research article related to the material you read in "Quantum Theory Cannot Hurt You" and "How atoms work"
You can find articles by checking out any online sources.  Here are some that may help:
science news
nature magazine
popular science
physicsworld