Question

The hour hand of a clock is 2.1 cm long.find the distance traveled by its tip in an hour

Answer 1

Answer:

Tip covered 4.4 cm

Step-by-step explanation:

How far does minute hand tip move in 20 minutes?

In 60 minute tip of minute hand make a complete circle.

60\text{ minutes}=2\pi

Now we find how much radian move in 20 minutes.

1\text{ minutes}=\frac{\pi}{30}

20\text{ minutes}=20\times \frac{\pi}{30}\Rightarrow \frac{2\pi}{3}

Length of minute had clock (r) = 2.1 cm

\theta=\frac{2\pi}{3}

Distance covered by tip of minute hand is l.

Formula: \theta=\frac{l}{r}

\frac{2\pi}{3}=\frac{l}{2.1}

l=\frac{2\pi}{3}\times 2.1\Rightarrow 4.4\text{ cm} \because \pi=\frac{22}{7}

Tip covered 4.4 cm