1. Two cars collide at an intersection. Car A, with a mass of 2000kg, is going from west to east, while car B, of mass 1500kg, is going from north to south at 17m/s. As a result of this collision, the two cars become enmeshed and move as one afterwards. In your role as an expert witness, you inspect the scene and determine that, after the collision, the enmeshed cars moved at an angle of 60 south of east from the point of impact. a) How fast were the enmeshed cars moving just after the collision? Express your answer in meters per second. b) How fast was car A going just before the collision? Express your answer in meters per second.

2. A 0.158 kg glider is moving to the right on a frictionless, horizontal air track with a speed of 0.800 m/s. It has a head-on collision with a 0.307 kg glider that is moving to the left with a speed of 2.29 m/s. Suppose the collision is elastic. a) Find the magnitude of the final velocity of the 0.158kg glider. Express your answer in meters per second. b) Find the direction of the final velocity of the 0.158kg glider. to the right or to the left? c) Find the magnitude of the final velocity of the 0.307kg glider. Express your answer in meters per second. d) Find the direction of the final velocity of the 0.307kg glider. to the right or to the left?

3. Canadian nuclear reactors use heavy water moderators in which elastic collisions occur between the neutrons (mass 1.0 u) and deuterons of mass 2.0 u. a) What is the speed of a neutron, expressed as a fraction of its original speed, after a head-on, elastic collision with a deuteron which is initially at rest? Express your answer using three decimal places. b) What is its kinetic energy, expressed as a fraction of its original kinetic energy? Express your answer using three decimal places. c) How many such successive collisions will reduce the speed of a neutron to 1/243 of its original value? Express your answer as a number of collisions.

4. A uniform cube with mass 0.300 kg and volume 0.0270 m3 is sitting on the floor. A uniform sphere with radius 0.400 m and mass 0.900 kg sits on top of the cube. a) How far is the center of mass of the two-object system above the floor? Express your answer with the appropriate units.