Question

A ball is thrown downward from a window in a tall building. its position at time t in seconds is s = 16t^2 + 32t, where s is in feet. how long (to the nearest tenth) will it take the ball to fall 211 feet

Answer 1

so When S is equal to 211
S = 16t^2 + 32t
211 = 16t^2 + 32t
Then, turn into a quadratic equation
0= 16t^2 + 32t - 211

Afterwards, simply find the roots of the equation by using your calculator formula 01.
you will be getting two answers,
t = 2.7666.... (correct to 3 significant figures)
t = -4.7666...(reject this because of its negative sign)

therefore, it will take 2.78 for the ball to fall 211 feet.