Step-by-step explanation:
The rocket's height h (in meters) after t seconds is given by:
[tex]h=67t-5t^2[/tex]
67 m/s is the initial upward velocity of the rocket. We need to find the values of t for which the rocket's height is 30 meters. So equation (1) becomes :
[tex]67t-5t^2=30[/tex]
[tex]67t-5t^2-30=0[/tex]
The above equation is a quadratic equation. We need to find the value of t.After solving the quadratic equation, we get the values of t are :
t = 0.464 seconds = 0.46 seconds
or
t = 12.936 seconds = 12.94 seconds
Hence, this is the required solution.