A ball is thrown straight upward from ground level with a velocity of 18m/s How much time passes before the ball strikes the ground? Disregard air resistance.
The displacement of the ball can be calculated using: s = ut + 1/2 at²; where u is the initial velocity and a is the acceleration. Because these are in opposite directions, one will be given a negative sign. s = 0 at ground level s = 18t - 1/2 x 9.81t² t(18 - 4.9t) = 0 t = 0; t = 3.67 seconds Thus, the ball will come back and strike the ground at 3.67 seconds.
