select the correct answer. an object is falling from a height of 7.5 meters. at what height will its…

select the correct answer. an object is falling from a height of 7.5 meters. at what height will its velocity be 7 meters/second? a. 49 meters b. 7.5 meters c. 7.0 meters d. 5.0 meters e. 2.5 meters

select the correct answer. an object is falling from a height of 7.5 meters. at what height will its velocity be 7 meters/second? a. 49 meters b. 7.5 meters c. 7.0 meters d. 5.0 meters e. 2.5 meters

Answer

Explanation:

Step1: Use the kinematic - equation

$v^{2}=v_{0}^{2}+2a\Delta h$. Here, the initial velocity $v_{0} = 0$ m/s, the acceleration $a = g= 9.8$ m/s², and $v = 7$ m/s. First, find the distance $\Delta h$ it has fallen. $v^{2}=0 + 2g\Delta h$, so $\Delta h=\frac{v^{2}}{2g}$.

Step2: Calculate $\Delta h$

Substitute $v = 7$ m/s and $g = 9.8$ m/s² into the formula: $\Delta h=\frac{7^{2}}{2\times9.8}=\frac{49}{19.6}=2.5$ m.

Step3: Find the height $h$

The initial height $h_{0}=7.5$ m. The height $h$ at the given - velocity is $h=h_{0}-\Delta h$. So $h = 7.5−2.5 = 5.0$ m.

Answer:

D. 5.0 meters