Q. A father racing his son has 1/2 the kinetic energy of the son, who has 1/3 the mass of the father. The father speeds up by 1.8 m/s and then has the same kinetic energy as the son. What are the original speeds of (a) father and (b) son?
Q. Suppose two kids get on a 4 meter long teeter-totter. The one on the right creates a CW torque of 350 Newton-meters (Nm). Quite by coincidence, when the other kid sits at 1 meter from his end they balance perfectly. How much does second kid weigh?