While visiting the amusement park, Sarah and Sam choose to ride the bumper cars while their instructor records video of their collisions. Back in the classroom, the students analyze a head-on-collision between Sarah and Sam's two cars. The velocity of each car after the collision is equal to the velocity of the other car before the collision (i. e., the cars switch velocities). What can the students infer about the masses of the bumper cars? A) Their masses are equal because both momentum and kinetic energy are conserved.
B) Their masses are unequal because both momentum and kinetic energy are conserved.
C) Their masses are unequal because neither momentum nor kinetic energy are conserved.
D) Their masses are unequal because neither momentum nor kinetic energy are conserved.

Amass m = 74 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius r = 18.4 m and finally a flat straight section at the same height as the center of the loop (18.4 m off the ground). since the mass would not make it around the loop if released from the height of the top of the loop (do you know why? ) it must be released above the top of the loop-the-loop height. (assume the mass never leaves the smooth track at any point on its path.) 1. what is the minimum speed the block must have at the top of the loop to make it around the loop-the-loop without leaving the track? 2. what height above the ground must the mass begin to make it around the loop-the-loop? 3. if the mass has just enough speed to make it around the loop without leaving the track, what will its speed be at the bottom of the loop? 4. if the mass has just enough speed to make it around the loop without leaving the track, what is its speed at the final flat level (18.4 m off the ground)? 5. now a spring with spring constant k = 15600 n/m is used on the final flat surface to stop the mass. how far does the spring compress?