A force in the negative direction of an x axis is applied for 27 ms to a 0.24 kg ball initially moving at 16 m/s in the positive direction of the axis. The force varies in magnitude, and the impulse has magnitude 45.1 N s. (a) What is the ball's velocity (including sign for direction) just after the force is applied? (b) What is the average magnitude of the force on the ball?