Question

10. The end of a 60 cm long
pendulum describes an arc of 20
cm. Find the angle through
which the pendulum swings.​

Answer 1

Answer:

There is your answer↓

Step-by-step explanation:

length of pendulum = radius of circle, r = 60cm

a/c to question, we have to find angle through which it swings when its tip describes an arc of length 16.5cm.

so, arc length , l = 16.5 cm

let subtended angle = α.

use formula, \boxed{\bf{\theta=\frac{l}{r}}}

θ=

r

l

so, \theta=\alphaθ=α , l = 16.5cm

and r = 60cm

so, α = 16.5/60 = 3.3/12 = 1.1/4 = 11/40 rad

we know, π rad = 180°

so, 1 rad = (180/π)°

so, 11/40 rad =[ (180/π) × 11/40 ]°

= 180/(22/7) × 11/40

= 180 × 7/22 × 11/40

= 9 × 7/4

= 63/4 = 15° (3/4 × 60)' [ we know, 1° = 60']

= 15° 45'

Therefore the angle through which pendulum swings is 15° 45'

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Answer 2

Answer:

The angle through which pendulum swings is 15° 45'

Step-by-step explanation:

length of pendulum = radius of circle, r = 60cm

a/c to question, we have to find angle through which it swings when its tip describes an arc of length 16.5cm.

so, arc length , l = 16.5 cm

➡️ let subtended angle = α.

use formula, $\boxed{\bf{\theta=\frac{l}{r}}}$

so, $\theta=\alpha, l = 16.5cm$

and r = 60cm

so, α = 16.5/60 = 3.3/12 = 1.1/4 = 11/40 rad

we know, π rad = 180°

so, 1 rad = (180/π)°

so, 11/40 rad =[ (180/π) × 11/40 ]°

= 180/(22/7) × 11/40

= 180 × 7/22 × 11/40

= 9 × 7/4

= 63/4 = 15° (3/4 × 60)' [ we know, 1° = 60']

= 15° 45'

Therefore the angle through which pendulum swings is 15° 45'