Diagnostic test  Are you ready for Physics 131?  The first midterm is 4 weeks off.  Ideally you shouldn't wait that long to find out.  The five questions below are not trick questions.  They are the kind of thing which is needed to pass physics 131 and which we will not be spending time on because we assume you remember well how to do these things.  Some of you will need to review math.  But the course will go so fast that you will not likely have time.  Physics 125 is more humane and will give you much more time for review.  Physics 125/126/127 covers exactly the same material as Physics 131.  Both Physics 126 and Physics 127 are offered during the summer, so you won't have to fall behind if you switch to Physics 125.

Give yourself 15 minutes maximum.  Write out answers.  Then look at the solutions and grade yourself.  I hope your got 80% right.

1. "milli" means divided by 1000 as in millimeter is a meter divided by 1000.  "pico" means divided by 1012.  If a molecule moves a picometer in a millisecond, what is its speed in m/s (express as a power of 10).
2. What is sin(45o) (use an elementary mathematical expression, not a calculator.)  Do the same for sin(-45o).
3. Consider the graph below.  It shows the position of two different objects as they change in time.  Object A corresponds to the straight line, and object B to the curved line.

a. Which object is ahead at time 0?
b. Which object has larger velocity at time t=2.5 s?
c. At what time (approximately) do the two objects have the same velocity?
d. What is the velocity of object A at t=4 s?
4. Given that x + 3y = 20 and that 2x - y = 10, find x and y.
5. The clock says 10:00 o'clock.  The sun, shown schematically below, is directly overhead (but very far away.)  The hour hand (short hand) is 1.00 m long.  How long is the shadow of the hour hand on the level ground below?  Your answer should be a simple exact mathematical formula.  If you don't get it that way, give a numerical result from your calculator for half credit