Solve the all parts of given problem:
Problem: A quarterback throws a football straight toward a receiver with an initial speed of 16.0 m/s, at an angle of 31.5° above the horizontal. At that instant, the receiver is 17.5 m from the quarterback.
Part A: In what direction should the receiver run in order to catch the football at the level at which it was thrown?
Part B: With what constant speed should the receiver run?
I need help to find with what constant speed the receiver run.