Question

15. The minute hand of a circular clock is 11 cm long. How far does the tip of the minute hand
move in 2 hours? (Take = 3.14)
​

Answer 1

Step-by-step explanation:

As, we are given the length of the minute hand of the clock.

And we can see from the above figure that tip of the minute hand forms the circle

When it finishes one complete round. i.e. In one hour.

And the radius of the circle will be the length of the minute hand.

So, distance made by the tip of minute hand in 2 hour = Circumference of the circle made by the minute hand.

As, we know that the circumference of the circle is given as, 2πr.

Where, r is the radius of the circle.

And here radius, r = 11cm.

So, circumference of the circle made will be,

$\sf \qquad \qquad⇒ 2π 11cm$

( it is given there to take the value of pie = 3.14)

$\sf \qquad \qquad⇒2 \times 3.14 \times 11$

$\sf \qquad\qquad⇒ 3.14 \times 22$

$\sf\qquad\qquad⇒ \frac{314}{100} \times 22$

$\sf \qquad \qquad⇒ \frac{314 \times 22}{100}$

$\sf\qquad\qquad⇒ \frac{6908}{100}$

$\sf \qquad \qquad⇒69.08$

Hence the tip of the minute hand moves 69.08 cm in one hour.

Answer 2

Given :-

In 1 hour, minute hand completes one round means makes a circle.

Radius of the circle(r) =15cm

To find :-

Circumference of circular clock =2πr

Solution :-

Circumference of a circular clock :-

$\sf⟹ 2 × \pi \: \times r$

$\sf{⟹ 2×3.14×15}$

$\sf⟹ 94.2cm$

★ Therefore, the tip of the minute hand moves 94.2cm in 1 hour.