The equation y = -6t^2 + 51t describes the height (in feet) of a projectile launched from the surface of Mars at 51 feet per second. In how many seconds will the projectile first reach 120 feet in height?
+14913 In how many seconds will the projectile first reach 120 feet in height?
Hello Guest!
\(f(t)=-6t^2+51t\\ \frac{df(t)}{dt}=-12t+51=0\\ t=4.25\)
\(h_{max}=-6\cdot 4.25^2+51\cdot 4.25\)
\(h_{max}=\color{blue}108.375\ feet\)
The projectile cannot reach a height of 120 feet.
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+36916 120 = -6t^2 + 51 t
-6t^2 + 51 t -120 = 0 Quadratic formula show t = imaginary numbers ..... no answer ...as asinus found !
