the height of an object at time t ≥ 1 is given by h(t)=t² - 16/t + 15. what is the velocity of the object at…

the height of an object at time t ≥ 1 is given by h(t)=t² - 16/t + 15. what is the velocity of the object at time t = 3? a 0.815 b 7.778 c 18.667 d 21.089
Answer
Explanation:
Step1: Recall velocity - height relationship
Velocity $v(t)$ is the derivative of height $h(t)$. Given $h(t)=t^{2}-\frac{16}{t}+15=t^{2}-16t^{- 1}+15$.
Step2: Differentiate $h(t)$
Using the power - rule $\frac{d}{dt}(t^{n})=nt^{n - 1}$, we have $v(t)=h^\prime(t)=2t+16t^{-2}=2t+\frac{16}{t^{2}}$.
Step3: Evaluate $v(t)$ at $t = 3$
Substitute $t = 3$ into $v(t)$: $v(3)=2\times3+\frac{16}{3^{2}}=6+\frac{16}{9}=\frac{54 + 16}{9}=\frac{70}{9}\approx7.778$.
Answer:
B. 7.778