Have you ever gone to a restaurant and ordered a glass of water with a straw in it? When you look at the glass, the straw seems to be broken! Why does that happen? Write a paragraph and/or draw a diagram explaining what is happening in reference to the light. Hint: Think about the speed of light when it travels through different materials and what might happen when light moves from one material to another.

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)