Question

If a pendulum 20 centimeters long swings to an angle of from its center on each side, then find the length of the arc from A to B. (JUSTIFY)

Answer 1

length of arc AB is 20.93 cm

Explanation:

length of the pendulum has been given as 20 cm

When it swings to an angle 30°from its center on each side, we have to find the length of the arc formed from A to B.

Since Length of arc = Length of the pendulum × θ

Where θ is in radians

Since 60° =
`(60)/(360)* 2\pi`

=
`(\pi )/(3)` radians

Now length of arc AB =
`20* (\pi )/(3)`

= 20×1.05

= 20.93 cm

Therefore, length of arc AB is 20.93 cm

Answer 2

20.93 cm

Explanation:

The formula to apply is ;

Ф/360° × 2πr

where Ф=60° and r=length of pendulum, 20 cm and π=3.14

60°/360° × 2×π×20 =20π/3 = 20.93 cm