Calculate the magnitude of the electric force between two charged balloons if one of the
balloons has a charge of 15 * 10 ^ - 8 C and the
other balloon has a charge of 7*10 ^ - 7 107C.
Their centers are located exactly .5 meters apart

Option (b)

Explanation:

Let the ball takes time t to reach the maximum height. The final velocity at maximum height is zero.

Use I equation of motion, we get

V = u + gt

0 = 3 - 9.8 x t

t = 0.306 s

As the air friction is negligible, so the ball takes same time to reach the hand of boy. Thus the time taken by the ball in air is

T = 2 t = 2 x 0.306 = 0.61 s