Question

You are helping with some repairs at home. You drop a hammer and it hits the floor at a speed of 12 feet per second. If the acceleration due to gravity (g) is 32 feet/second2, how far above the ground (h) was the hammer when you dropped it? Use the formula:A.8.5 feetB.1.0 footC.2.25 feetD.18.0 feet

Answer 1

Solution

Step 1:

Given data:

$\begin{gathered} v\text{ = 12} \\ \text{g = 32} \\ h\text{ = ?} \end{gathered}$

Step 2:

$\begin{gathered} v\text{ = }\sqrt{2gh} \\ \\ 12\text{ = }\sqrt{2\times32\times h} \\ \\ 12\text{ = }\sqrt{64h} \\ \\ Take\text{ square of both sides} \\ \\ 12^2\text{ = \lparen}\sqrt{64h})^2 \\ \\ 144\text{ = 64h} \\ \\ h\text{ = }\frac{144}{64}\text{ = 2.25 feet} \end{gathered}$

Final answer

C. 2.25 feet