select the correct answer.\na rock is dropped from a height of 2.5 meters. what is its velocity when it…

Explanation:

Step1: Identify the relevant formula

We use the kinematic - equation $v^{2}=v_{0}^{2}+2ax$. Since the rock is dropped, $v_{0} = 0$ m/s, the acceleration $a = g=9.8$ m/s² (acceleration due to gravity near the Earth's surface), and the displacement $x = 2.5$ m.

Step2: Substitute the values into the formula

Substituting $v_{0}=0$, $a = 9.8$ m/s², and $x = 2.5$ m into $v^{2}=v_{0}^{2}+2ax$, we get $v^{2}=0 + 2\times9.8\times2.5$. $v^{2}=49$.

Step3: Solve for $v$

Taking the square - root of both sides, $v=\sqrt{49}=7$ m/s.

Answer:

B. 7.0 meters/second