Uploaded by Nick Reichlin


Physics 291 – Spring 2021
Group Assignment 4
February 20, 2021
Extra credit opportunity:
You will receive double credit for a problem, if your solution is chosen as the sample solution.
An asteroid of mass m is on a collision course with Earth. It is observed to have speed v1 when it
is at a distance r1 from the center of the Earth. We are interested in its speed when it hits the
Earth. The radius of the Earth is RE , Earth’s mass is M .
1. The figure on the left shows the 1st relevant situation. Draw a sketch of the 2nd relevant situation and
collect the available information.
2. Write symbolic equations for the potential and kinetic energy in each of the situations.
3. Apply conservation of energy, U1 + K1 = U2 + K2 , and solve for the unknown v2 .
4. How do you know your answer makes sense?