After how many seconds will the ball hit the ground? h = -16t^2 + 12t + 40

Question

After how many seconds will the ball hit the ground? h = -16t^2 + 12t + 40

in progress 0
Trung Dũng 4 years 2021-08-26T19:49:36+00:00 1 Answers 20 views 0

Answers ( )

  1. yenoanh
    0
    2021-08-26T19:51:25+00:00
    Reply

    Answer:

    2 seconds

    Step-by-step explanation:

    h = -16t^2 + 12t + 40

    by the time the ball hit the ground, height (h) = 0

    0 = -16t^2 + 12t + 40

    solve time (t) using quadratic equation:  ax^2+bx+c=0

          – b ± \sqrt{b^2 - 4ac}

    x = —————————–

                  2a

    where:

    a = -16

    b = 12

    c = 40

    plugin values into the formula

          – 12 ± \sqrt{12^2 - 4 (-16) 40}

    t = ———————————-

                       2 (-16)

    t = -5/4 , t = 2

    therefore, the ball will hit the ground in 2 seconds

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )