A quarterback is trying to throw a football to a stationary receiver. The receiver is not directly in front of him, so the total velocity of the ball and the velocity of the quarterback has to be 20 m/s at an angle of 21.4 degrees from the vertical direction as shown in the sketch. If the quarterback is running at 8.9 m/s to his right (+x direction), how fast does the ball need to be thrown in m/s? In other words, what is the magnitude of the velocity of the ball?

Question

A quarterback is trying to throw a football to a stationary receiver.  The receiver is not  directly in front of him, so the total velocity of the ball and the velocity of the quarterback has to be 20 m/s at an angle of 21.4 degrees from the vertical direction as shown in the sketch.  If the quarterback is running at 8.9 m/s to his right (+x direction), how fast does the ball need to be thrown in m/s?  In other words, what is the magnitude of the velocity of the ball?