A disc, initially at rest, starts rotating about its own axis, with a constant angular acceleration of 0.2 rad/s2.The time taken by the disc to rotate by 10 rad is (in second)

Question

A disc, initially at rest, starts rotating about its own axis, with a constant angular acceleration of 0.2 rad/s2.The time taken by the disc to rotate by 10 rad is (in second) (A) 7.07 (B) 10 (C) 14.14 (D) 100

Tardigrade Admin · Accepted Answer

From the equation, θ =ω 0t+(1/2)α t2 Given, α =0.2 text rad/s2, text ω 0=0, text θ =10 text rad ⇒ 10=(1/2)(0.2)t2 ⇒ t2=100 ⇒ t=10 s

Q. A disc, initially at rest, starts rotating about its own axis, with a constant angular acceleration of 0.2 rad/s2.The time taken by the disc to rotate by 10 rad is (in second)

7.07

10

14.14

100

From the equation, $θ = ω_{0} t + \frac{1}{2} α t^{2}$ Given, $α = 0.2 r a d / s^{2}, ω_{0} = 0, θ = 10 r a d$ $\Rightarrow$ $10 = \frac{1}{2} (0.2) t^{2}$ $\Rightarrow$ $t^{2} = 100$ $\Rightarrow$ $t = 10 s$

Q. A disc, initially at rest, starts rotating about its own axis, with a constant angular acceleration of 0.2 rad/s2.The time taken by the disc to rotate by 10 rad is (in second)

7.07

10

14.14

100

From the equation, θ=ω0​t+21​αt2 Given, α=0.2rad/s2,ω0​=0,θ=10rad ⇒ 10=21​(0.2)t2 ⇒ t2=100 ⇒ t=10s

From the equation, $θ = ω_{0} t + \frac{1}{2} α t^{2}$ Given, $α = 0.2 r a d / s^{2}, ω_{0} = 0, θ = 10 r a d$ $\Rightarrow$ $10 = \frac{1}{2} (0.2) t^{2}$ $\Rightarrow$ $t^{2} = 100$ $\Rightarrow$ $t = 10 s$