Question

8. The needle of a record player moves 7.2 cm when playing a particular record. If the
record makes 900 revolutions, find the width of the groove.​

Answer 1

Given :–

• The needle of a record player moves when playing a particular record = 7.2cm.
• Number of revolutions = 900

To Find :–

• Width of the groove.

Solution :–

So, here find the width of the groove = $\frac{Total \: distance \: covered \: by \: the \: needle}{No. \: of \: revolutions - 1}$

→ $\frac{7.2}{900 - 1}$

→ $\frac{7.2}{899}$

→ $\frac{72}{899 \times 10}$

→ $\frac{72}{8990}$

→ $\frac{36}{4495}$

→ 0.00801cm

We know that,

• 100 centimeters (cm) = 10,00,000 micrometer (um)

And,

• 1cm = 10,000 um

So,

For converting cm into um, we need to multiply the cm by 10000.

I.e., 0.00801 × 10,000

→ 80.1 um

Answer 2

Answer:

I know the ans

Step-by-step explanation:

Distance covered by a needle in playing a particular record = 7.2 cm Number of revolutions = 900 Width of the groove = Distance covered / (Number of revolutions – 1) = 7.2 / (900−1) = 7.2/ 899 = 0.00801 cm.

If it was helpful thank me....