A ball is thrown vertically upwards at 19.6 m/s.For its complete trip (up and back down to the starting position),its average speed is:
A)19.6 m/s.
B)9.80 m/s.
C)4.90 m/s.
D)not given.

Question

Quizplus · Accepted Answer

When the ball is thrown upwards, it reaches a maximum height of h = (v^2)/(2g) = (19.6^2)/(2*9.8) = 19.6 meters.

The time taken to reach this height can be found using the formula t = v/g = 19.6/9.8 = 2 seconds.

The total time for the ball to complete its trip is therefore 2 + 2 = 4 seconds.

The distance travelled by the ball during this time is twice the maximum height, which is 2*19.6 = 39.2 meters.

Therefore, the average speed of the ball is distance/time = 39.2/4 = 9.8 m/s.

So, the best choice is B, which is 9.80 m/s.

A Ball Is Thrown Vertically Upwards at 19