You and your friends are doing physics experiments on a frozen pond that serves as a frictionless, horizontal surface. sam, with mass 73.0 kg, is given a push and slides eastward. abigail, with mass 57.0 kg, is sent sliding northward. they collide, and after the collision sam is moving at 40.0^\circ north of east with a speed of 7.00 m/s and abigail is moving at 18.0^\circ south of east with a speed of 9.40 m/s. what was the speed of each person before the collision?
a. sam's speed:
b. abigail's speed:
c. by how much did the total kinetic energy of the two people decrease during the collision?