Choose the one alternative that best completes the statement or answers the question.
-A rocket is shot straight up in the air from the ground at a rate of 80 feet per second. The rocket is tracked by a range finder that is 431 feet from the launch pad. Let $d$ represent the distance from the rocket to the range finder and t represent the time, in seconds, since "blastoff". Express $\mathrm { d }$ as a function of $t$
A) $\mathrm { d } ( \mathrm { t } ) = 431 ^ { 2 } + ( 80 \mathrm { t } ) ^ { 2 }$
B) $\mathrm { d } ( \mathrm { t } ) = \sqrt { 80 ^ { 2 } + ( 431 \mathrm { t } ) ^ { 2 } }$
C) $\mathrm { d } ( \mathrm { t } ) = 431 + 80 \mathrm { t } ^ { 2 }$
D) $d ( t ) = \sqrt { 431 ^ { 2 } + ( 80 t ) ^ { 2 } }$

Question

Quizplus · Accepted Answer

The distance from the rocket to the range finder can be found using the Pythagorean theorem, where one leg is the constant distance from the launch pad to the range finder (431 feet) and the other leg is the distance the rocket has traveled upwards (80t). The correct expression is $d(t) = \sqrt{431^2 + (80t)^2}$.

Choose the One Alternative That Best Completes the Statement or Answers