1/18/11

Post date: Feb 18, 2011 2:17:10 PM

• • Bell Ringer: Fessic the giant (135 kg) halls himself and 3 others up a rope to the top of the 125 m cliffs of insanity. The 3 people have masses of 52 kg, 68 kg, and 74 kg. If they start at rest at the bottom of the cliffs, and Fessic applies a constant upward force of 3450 N, how long does it take them to reach the top?

  • Drag / air resistance

• Meteor problem (due Tuesday)

  • • It has been predicted that in the future, we will anger an alien race of giant bugs, who will then sling meteors at us.

    • One such meteor is headed toward Earth. Government officials have tasked you with trying to slow the meteor sufficiently that it hits the Earth softly so we can study the alien propulsion technology. Your task is to calculate how much force needs to be applied to the meteor (using a rocket that has been attached to the meteor) to stop the meteor at Earth's surface.

    • Here's what we know: The meteor has a mass of 2.79 x 10^6 kg, and is currently travelling toward Earth at 585 m/sec. It is 1.96 x 10^7 meters away from Earth's surface. The alien propulsion technology is pushing the meteor toward Earth wtih 125,000 N of force. Solar winds are acting in our favor, pushing the meteor away from Earth with 10,000 N of force. The meteor's weight will vary as it gets closer to Earth, but you can assume it has an average weight of 1.116 x 10^7 N.

    • Be sure to write out all given information, include a sketch of the situation that shows all the forces acting on the meteor, and solve for the force needed to stop the meteor at Earth's surface. Work quickly; the meteor is coming!

• Chapter 5 Test Wednesday