An object is launched vertically upward from a 25 foot platform and is modeled by the function s(t)=-16t^2+11t+25
The object will fall back to the ground after
A)1.64 seconds
B)0.95 seconds
C)-0.95 seconds
D)1.64 seconds
Because _____ cannot be a solution
The object will fall back to the ground when s(t) = 0, so we need to solve the equation -16t^2 + 11t + 25 = 0 for t.
Using the quadratic formula, we get:
t = [-11 ± √(11^2 - 4(-16)(25))] / 2(-16)
t = [-11 ± √(121 + 1600)] / -32
t = [-11 ± √1721] / - 32
The square root of 1721 is approximately 41.48, and when solved further we get:
t ≈ (-11 + 41.48)/-32 = 1.64 seconds or t ≈ (-11 - 41.48)/-32 = -0.95 seconds.
Therefore, the correct answer is:
D) 1.64 seconds
Because a negative time value (C) -0.95 seconds is not a meaningful solution in this case.