Final answer:
The final velocity of a ball dropped from rest and falling for 4 seconds is 39.2 m/s, directed downward.
Step-by-step explanation:
The student has asked about the final velocity of a ball dropped from rest and falling for 4 seconds, neglecting air resistance. To find the final velocity of the ball, we use the formula for the velocity of an object undergoing uniform acceleration due to gravity, which is v = gt, where v is the final velocity, g is the acceleration due to gravity (9.8 m/s² on Earth), and t is the time in seconds. Therefore, the final velocity v after 4 seconds is 9.8 m/s² × 4 s = 39.2 m/s, directed downward towards the ground.