Question

A fly wheel is accelerated uniformly from rest and rotates through 5 rad in the first second. The angle rotated by the fly wheel in the next second, will be ______.

Options

• 7.5 rad

• 15 rad

• 20 rad

• 30 rad

Answer 1

A fly wheel is accelerated uniformly from rest and rotates through 5 rad in the first second. The angle rotated by the fly wheel in the next second, will be 15 rad.

Explanation:

We have θ = ω₀t + `1/2`αt² 

Here, ω₀ = 0, θ = 5 rad and t = 1 sec

⇒ 5 = `1/2`α × 1² ⇒ α = 10 rad/s²

Now, θ_n = `alpha/2(2"n"-1)`+ ω₀ 

θ₂ = `10/2(2xx2-1)+0`

= 15 rad/sec.