Question 4 (10 points) If a toy rocket is lounched vertically upward from ground level with an initial velocity of 128 feet per second,then its height. h, after t seconds is given by the equation h(t)=-16t^2+128t (air resistance is neglected) How long did it take the toy rocket to reach its maximum height? 6 seconds b 4 seconds 2 seconds 1 second

## Step 1The given equation is a quadratic equation in the form of , where , , and . The maximum height of the rocket is reached at the vertex of the parabola represented by this equation.## Step 2The x-coordinate of the vertex of a parabola given by the equation is given by the formula .### **The formula for the x-coordinate of the vertex is **## Step 3Substitute the values of and into the formula to find the time at which the maximum height is reached.### **Substitute and into the formula to get \( -128/(2*-16) \)**## Step 4Calculate the value of \( -128/(2*-16) \) to get 4.