Lots of Questions

[Quelloquialism]

Sorry, I'm stupid. This is pretty much only Physics.

1) Horizontal circular platform rotating about a frictionless axle with a weight on it. You're given the radius, mass, and initial angular speed of the platform, and then the mass, initial distance from the center, and final distance from the center for the weight. How do you find the final angular speed?

2) A rigid container holding water is punctured at a specified point, and you're given the dimensions of the container. How do you find the speed of the water escaping through the hole?

3) Given the acceleration of gravity, what is the relation between period and length of a pendulum?

4) Given the intensity of a sound, how do you find the sound's decibel level?

5) A weight hanging on a spring oscillates in simple harmonic motion, and you're given the spring's stretched distance when stationary, the mass of the weight, and the extra distance the spring was stretched when let go to start the motion. How do you find the period of vibration and maximum speed of the weight?

6) Given the index of refraction in a medium, how do you find the speed of light in the same medium?

7) Given the velocity of an object (near c), how do you measure the extent of time and length contraction?

8) How do you find the wavelength of an object given its mass and velocity?

9) If you have nearsightedness that prevents you from seeing beyond a given distance, what power in diopters would you need for a corrective lens? (I guessed based on the old joke about measuring velocities in hertz per diopter instead of meters per second that the answer was the reciprocal of the distance, but I have no confidence in this answer, as it was just a guess)

[jscherm]

[bradp]

#1- conservation of angular momentum
[unparseable or potentially dangerous latex formula]

the second term has a one half because the inertia of solid disks (the platform) is [unparseable or potentially dangerous latex formula]
the radius of the platform stays the same, but the radius of the guy changes

i missed this because i did r, not r^2 for some reason. Ended up getting a 92, top physics was a 104. Anyone get higher than that?

[jscherm]

Top physics at the O'Connor meet was a 112...definitely not me, though.

(Top bio was an 80, and I think the top chem was also a 112)