Physics Challenge

Rules for Physics Challenge

  • We will have a monthly Physics challenge problem.
  • The problem is meant for a team of two students. If you prefer, you can work alone, but we are not going to allow teams with more than two students
  • You can discuss the problem with other people but cannot solicit solutions (including over web) from anyone.
  • You do not have to complete the entire problem to be considered for the competition. We (physics faculty) are simply going to pick the best solution from the pool.
  • The winner of the competition will get a cash prize of $50 to be shared among the two students. We are planning to display their names in the Physics office/web page as well.
  • You must submit your solution by the deadline posted on the problem sheet.
  • If you want any clarifications on the problem, please contact Dr. Biswas (tbiswas@loyno.edu)

 

The first PHYSICS CHALLENGE Problem

(deadline for solutions Oct. 6, 2011)

The Asteroid Menace

We all know that an asteroid was the most likely responsible for the mass extinction of dinosaurs in the tertiary era. Scientists believe that the asteroid had to be around 10 km in radius.

(a) Assuming the asteroid has typical density and speed, estimate the kinetic energy it possesses. How does it compare with the energy release in an atom bomb? Let us now envision the familiar Hollywood scenario: Alas, an asteroid (of the size that destroyed the dinosaurs) is heading straight at us! Is there anything that we can do to avoid the impending doomsday?

(b) Level 1: How about trying to launch a rocket which collides with the asteroid but is unable to break it. Can you deviate the asteroid enough? Assume that you detect the presence of the asteroid when it just reaches the orbit of Mars. (Between Mars and Jupiter there are several asteroid orbits, hence it is difficult to pick out any dangerous asteroid path before it is closer then the Mars orbit.) Use reasonable numbers in your calculations. Hint: It is not the launch mass of the rocket that matters, but what the rocket mass is when it is traveling in space.

(c) Level 2: If you didn’t succeed, how about trying to break the asteroid? Say the rocket breaks the rock into two fragments. You can assume energy conservation and see whether this works.

(d) Level 3: If the above didn’t work, or may be it did but you want to improve your odds (which, by the way, is not a bad idea under the circumstances) you decide to explode a bomb the moment the rocket hits the asteroid. In other words, you are able to add energy. Just to estimate, imagine the whole rocket being made of TNT. Do we have any hopes of survival?

(e) If not, is there anything else we can do? PS: There are several different parameters/considerations you can introduce. For instance, the asteroid may not be headed straight at the center of the earth, but slightly off it. The trajectory of the asteroid need not be straight, and it may gain or loose speed as it comes to us, etc etc.. You might want to do some numerical calculations as well. This is obviously an open-ended problem.

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