College

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 [tex]g[/tex] is 32 feet/second[tex]^2[/tex], how far above the ground [tex]h[/tex] was the hammer when you dropped it?

Use the formula:

[tex]v = \sqrt{2gh}[/tex]

A. 18.0 feet
B. 2.25 feet
C. 1.0 foot
D. 8.5 feet

Answer :

To solve the problem of determining the height from which the hammer was dropped, we use the formula for velocity when an object is dropped from a certain height:

[tex]\[ v = \sqrt{2gh} \][/tex]

Where:
- [tex]\( v \)[/tex] is the velocity with which the hammer hits the ground (12 feet per second),
- [tex]\( g \)[/tex] is the acceleration due to gravity (32 feet/second²),
- [tex]\( h \)[/tex] is the height we need to find.

We want to solve for [tex]\( h \)[/tex]. Let's rearrange the formula to make [tex]\( h \)[/tex] the subject:

1. Square both sides to remove the square root:

[tex]\[ v^2 = 2gh \][/tex]

2. Solve for [tex]\( h \)[/tex] by dividing both sides by [tex]\( 2g \)[/tex]:

[tex]\[ h = \frac{v^2}{2g} \][/tex]

Now, plug in the given values:

- [tex]\( v = 12 \)[/tex] feet/second
- [tex]\( g = 32 \)[/tex] feet/second²

Substitute these values into the equation:

[tex]\[ h = \frac{12^2}{2 \times 32} \][/tex]

[tex]\[ h = \frac{144}{64} \][/tex]

[tex]\[ h = 2.25 \][/tex] feet

Thus, the height from which the hammer was dropped is 2.25 feet. Therefore, the correct answer is:

B. 2.25 feet