Answered

The equation for a projectile's height versus time is [tex]h(t)=-16 t^2+v_0 t+h_0[/tex].

A tennis ball machine serves a ball vertically into the air from a height of 2 feet, with an initial speed of 120 feet per second. Which equation correctly models the ball's height as a function of time?

A. [tex]h(t)=-16 t^2-2 t+120[/tex]

B. [tex]h(t)=-16 t^2+120 t+2[/tex]

C. [tex]h(t)=-16 t^2+2 t+120[/tex]

D. [tex]h(t)=-16 t^2-120 t-2[/tex]



Answer :

To determine which equation correctly models the ball's height as a function of time, we can use the given formula for the height of a projectile:

[tex]\[ h(t) = -16t^2 + v_0 t + h_0 \][/tex]

Here's a step-by-step solution:

1. Identify Initial Height ( [tex]\( h_0 \)[/tex] ) and Initial Speed ( [tex]\( v_0 \)[/tex] ):
- The problem states that the ball starts at a height of 2 feet.
- Therefore, [tex]\( h_0 = 2 \)[/tex] feet.
- The initial speed with which the ball is launched is 120 feet per second.
- Thus, [tex]\( v_0 = 120 \)[/tex] feet/second.

2. Substitute the Given Values into the Formula:
- Plugging in the initial height [tex]\( h_0 = 2 \)[/tex] and initial speed [tex]\( v_0 = 120 \)[/tex]:
[tex]\[ h(t) = -16t^2 + 120t + 2 \][/tex]

3. Verify the Correct Equation:
- Now, we match our derived equation [tex]\( h(t) = -16t^2 + 120t + 2 \)[/tex] with the provided options:
- A. [tex]\( h(t) = -16t^2 - 2t + 120 \)[/tex]
- B. [tex]\( h(t) = -16t^2 + 120t + 2 \)[/tex]
- C. [tex]\( h(t) = -16t^2 + 2t + 120 \)[/tex]
- D. [tex]\( h(t) = -16t^2 - 120t - 2 \)[/tex]

4. Conclusion:
- The equation [tex]\( h(t) = -16t^2 + 120t + 2 \)[/tex] corresponds to option B.

Hence, the correct equation that models the ball's height as a function of time is:
[tex]\[ \boxed{B} \][/tex]