Crazy Cat Problems

Resting
Originally uploaded by Ewwwww.

In the physics class that I'm teaching, I've been told to create a problem each week for the students to solve.

Here is last week's:
"My crazy cat, Theo (aka “little baby”), convinces me to go bungee jumping. He leads me to a bridge that is 60m above molten lava. Before going on this trip, I go on a diet and slim down to 75kg. The bungee cord is 15m long and has a spring constant of k= 50 N/m. Does Theo love me, or want to see the end of me?"

Here is this week's:
"My crazy cat, Theo (aka “little baby”), steals my girlfriend’s Saturn and picks up a few General Physics I Students for a joy-ride. They figure out that the braking distance from 60km/h is 20m.

They head up the BQE and spot me 150m away. Theo decides to steer right at me and speeds up to 120 km/h. When they are 100m away my girlfriend shows up. In that instant, a nameless A+ Gen Phys I Student convinces Theo to hit the brakes.

Assume that the maximum braking force is independent of speed. Use the Kinetic Energy-Work Theorem to figure out if I owe my life to the nameless A+ Gen Phys I Student."

Solve them, if you dare.