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Calculate Angular Acceleration of Rotating Particle After Fixed Time

A particle is rotating in a circular path and at any instant its motion can be described as θ=5t440t33.\theta = \frac{5t^4}{40} - \frac{t^3}{3}. The angular acceleration of the particle after 10 seconds is _______ rad/s2\text{rad/s}^2.

Options

A

150

B

120

C

130

Correct
D

170

Step-by-Step Solution

The angular position θ\theta of the particle as a function of time tt is given by: θ(t)=5t440t33=t48t33\theta(t) = \frac{5t^4}{40} - \frac{t^3}{3} = \frac{t^4}{8} - \frac{t^3}{3}

The angular velocity ω(t)\omega(t) is the first derivative of the angular position with respect to time: ω(t)=dθdt=ddt(t48t33)=4t383t23=t32t2\omega(t) = \frac{d\theta}{dt} = \frac{d}{dt}\left(\frac{t^4}{8} - \frac{t^3}{3}\right) = \frac{4t^3}{8} - \frac{3t^2}{3} = \frac{t^3}{2} - t^2

The angular acceleration α(t)\alpha(t) is the second derivative of the angular position with respect to time: α(t)=dωdt=ddt(t32t2)=3t222t\alpha(t) = \frac{d\omega}{dt} = \frac{d}{dt}\left(\frac{t^3}{2} - t^2\right) = \frac{3t^2}{2} - 2t

Substituting t=10 st = 10\text{ s} into the expression for angular acceleration: α(10)=3(10)222(10)\alpha(10) = \frac{3(10)^2}{2} - 2(10) α(10)=300220=15020=130 rad/s2\alpha(10) = \frac{300}{2} - 20 = 150 - 20 = 130\text{ rad/s}^2

Thus, the angular acceleration of the particle after 10 seconds10\text{ seconds} is 130 rad/s2130\text{ rad/s}^2.

Correct Option: C

Calculate Angular Acceleration of Rotating Particle After Fixed Time | Physics PYQ Solution - JEE Challenger