Consider a 20 kg uniform circular disk of radius 0 . 2 m . It is pin supported at its center and is at rest initially. The disk is acted upon by a constant force F = 20 N through a massless string wrapped around its periphery as shown in the figure. Suppose the disk makes n number of revolutions to attain an angular speed of 50 rad s - 1 . The value of n , to the nearest integer, is _______ . [Given : In one complete revolution, the disk rotates by 6 . 28 rad ]

Question

Consider a 20 kg uniform circular disk of radius 0 . 2 m . It is pin supported at its center and is at rest initially. The disk is acted upon by a constant force F = 20 N through a massless string wrapped around its periphery as shown in the figure. Suppose the disk makes n number of revolutions to attain an angular speed of 50 rad s - 1 . The value of n , to the nearest integer, is _______ . [Given : In one complete revolution, the disk rotates by 6 . 28 rad ],

MARKS App · Accepted Answer

α = τ I = F . R . m R 2 / 2 = 2 F m R α = 2 × 200 20 × 0 . 2 = 10 rad / s 2 ω 2 = ω 0 2 + 2 α Δ θ 50 2 = 0 2 + 2 10 Δ θ ⇒ Δ θ = 2500 20 Δ θ = 125 rad No. of = 125 2 π ≈ 20 revolution

Search any question & find its solution

Looking for more such questions to practice?