your equation should be
s = -4t^2 - 6t + 100
you want to know when s = 0
4t^2 + 6t - 100 = 0
2t^2 + 3t - 50 = 0
t = (-3 ±√409)/4
= appr 4.3 seconds or a negative, which we will reject
If an object is thrown downward with an initial velocity of
v0, then the distance it travels is given by
s=4.9t sqrt 2 +v v0t. An object is thrown downward from an airplane 100 m from the ground, with an initial velocity of 6
m/sec. How long does it take for the object to reach the ground?
1 answer