Joe is setting up a test run for a new roller coaster. The coaster car and test dummy have a combined mass of 520 kg, and the portion of the coaster they are
testing drops from a hill into a circular loop 10.0 meters across. What is the minimum speed
the car must be going at the top of the loop? What is the minimum height the hill leading
into the loop must be (measured from the bottom of the loop to the top of the hill)?

On a horizontal frictionless surface, a small block with mass 0.200 kg has a collision with a block of mass 0.400 kg. immediately after the collision, the 0.200 kg block is moving at 12.0 m/s in the direction 30° north of east and the 0.400 kg block is moving at 11.2 m/s in the direction 53.1° south of east. use coordinates where the +x-axis is east and the +y-axis is north.(a) what is the total kinetic energy of the two blocks after the collision (in ) what is the x-component of the total momentum of the two blocks after the collision? (indicate the direction with the sign of your ) what is the y-component of the total momentum of the two blocks after the collision? (indicate the direction with the sign of your answer.)