Question

Two gears are connected and are rotating simultaneously. The smaller gear has a radius of 3 inches, and the larger gear has a radius of 7 inches.
Part 1: What is the angle measure, in degrees and rounded to the nearest tenth, through which the larger gear has rotated when the smaller gear has made one complete rotation?

Part 2: How many rotations will the smaller gear make during one complete rotation of the larger gear?

Answer 1

Answer:

Part 1: Angle = 154.3°

Part 2: About 2.33 Rotations

Step-by-step explanation:

Part 1:

The arc length of a circle is given by the formula  $s=r\theta$

Where

• s is the arc length
• r is the radius of the circle
• $\theta$ is the angle

**The angle are in radians and we will use radian**

When smaller gear has made 1 complete rotations ($2\pi$ radians), the arc length traveled is $s=r\theta\\s=(3)(2\pi)\\s=6\pi$

Now, what angle is swept by the larger circle when it travels $6\pi$? Put in $s=6\pi$ and r is 7 to find $\theta$:

$s=r\theta\\6\pi=(7)\theta\\\theta= \frac{6\pi}{7}$

** Since $\pi$ radians is 180°, we plug in 180 into $\pi$ and find the degree measure:

$\frac{6\pi}{7}=\frac{6*180}{7}=154.3$

Angle = 154.3°

Part 2:

In one complete rotation of the larger gear, it travels a distance of:

$s=r\theta\\s=(7)(2\pi)\\s=14\pi$

We know that the smaller circle makes 1 rotation and travels $s=r\theta=(3)(2\pi)=6\pi$, so in $14\pi$ distance, it makes:

Rotations = $\frac{14\pi}{6\pi}=\frac{14}{6}=2.33$

About 2.33 Rotations