A ball is spun with angular acceleration α = 6 t 2 - 2 t where t is in second and α is in rad…

A ball is spun with angular acceleration α=6t2-2t where t is in second and α is in rad s-2. At t=0, the ball has angular velocity of 10 rad s-1 and angular position of 4 rad. The most appropriate expression for the angular position of the ball is
  1. 32t4-t2+10t
  2. t42-t33+10t+4
  3. 2t43-t36+10t+12
  4. 2t4-t32+5t+4

Solution

Given: α=6t2-2t

Using relation α=dωdt=6t2-2t

Integrating the above, 

10ωdω=0t6t2-2tdt

ω-10=2t3-t2

Now, ω=dθdt=10+2t3-t2

4θdθ=0t10+2t3-t2dt

Integrating the above relation, 

θ-4=10t+t42-t33

Thus, angular position of the ball is θ=t42-t33+10t+4.

Asked in: JEE Main 2022 (28 Jun Shift 2)

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