(Trig) Some Basic Astronomy Calculations...

In the constellation Orion, the two stars representing the shoulders are Betelgeuse, the red giant star, and Bellatrix. Say the distance at the moment between them is 204 light years. The distance from Betelgeuse to the earth is 429 light years, and the distance from Bellatrix to the earth is 243 light years. What is the angle formed between the earth and those two stars?






(Probability) Call His Bluff

It's poker night and the game is Texas Holdem. Now, get your poker face on and crunch those numbers!

You're sitting in the final round of betting with pocket rockets (a pair of Aces) in your hand. On the table there is an 8 of diamonds, 2 of hearts, 3 of spades, 4 of clubs, and the dealer just revealed a 6 of clubs. Two of your opponents just folded, and one is betting as if he had a 5 to complete the straight on the table.

What is the probability that your opponent has a 5 in his hand?
Here's a refresher on Texas Holdem

(Fluids) Water Gun Nozzle Design

You're creating a toy water gun, and are currently working on the nozzle design below. This is just a back-of-the-envelope calculation, so assume the flow is incompressible, and neglect any frictional effects. The water in the gun discharges freely to the atmosphere at the exit on the right. 

With these conditions, what's the gage pressure at the inlet?

  • 10.2 kPa
  • 10.8 kPa
  • 11.3 kPa
  • 12.7 kPa
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(Physics) Same Force on Two Blocks

The same horizontal force, of magnitude F, is applied to two different blocks, of mass m and 3m respectively. The blocks move on a frictionless surface and both blocks begin from rest. If each block moves the same distance as the force is applied, which one of the following sentences is true? 



(Physics) Kinetic Energy of Two Pieces


An explosion splits an object initially at rest into two pieces of unequal mass. Which piece has the greater kinetic energy?

(After 5 min, if you don't know, guess! Then learn from the solution for next time!)