Question

A ball is thrown straight down with a speed of Va2.00 from a building 40.00 meters high. How much S time passes before the ball reaches the ground? a.) -3.07s b.) - 2.46 s c.) =2.66s d.) =9.89s e.) None of the above.A ball is thrown straight down with a speed of Va2.00 from a building 40.00 meters high. How much S time passes before the ball reaches the ground? a.) -3.07s b.) - 2.46 s c.) =2.66s d.) =9.89s e.) None of the above.

Answer 1

Answer:

Option C is the correct answer.

Explanation:

Considering vertical motion of ball:-

Initial velocity, u =  2 m/s

Acceleration , a = 9.81 m/s²

Displacement, s = 40 m

We have equation of motion s= ut + 0.5 at²

Substituting

   s= ut + 0.5 at²

    40 = 2 x t + 0.5 x 9.81 x t²

   4.9t²  + 2t - 40 = 0

   t = 2.66 s   or t = -3.06 s

So, time is 2.66 s.

Option C is the correct answer.