A fan initially rotating at 60 rad/sec clockwise accelerates and acquires an angular velocity of 110 rad/sec clockwise. If the angular acceleration of the fan is constant and it takes 2 sec to change its angular velocity, find the angular acceleration of the fan. A. 50 rad/sec2 in counterclockwise direction B. 25 rad/sec2 in counterclockwise direction C. 25 rad/sec2 in clockwise direction D. 50 rad/sec2 in clockwise direction

Collegedunia Team

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The correct option is (C)

The equation of rotational motion for constant angular acceleration is given by

ω_f = ω_i + αt

⇒ α = $\frac{\omega_f - \omega_i}{t}$

Where,

ω_f = final angular velocity
ω_i = initial angular velocity
α = angular acceleration
t = time taken to reach final angular velocity from initial angular velocity.

Taking the clockwise direction as -ve and counterclockwise as +ve.

Given,

Initial angular velocity of the fan, ω_i = – 60 rad/s

final angular velocity of the fan, ω_f = – 110 rad/s

Time taken, t = 2 sec

Using the equation of rotational motion, angular acceleration (α) of the fan, is given by

α = $\frac{(-110)-(-60)}{2}$ = – $\frac{50}{2}$

⇒ α = – 25 rad/sec²

Negative sign shows that the angular acceleration of the fan is in the clockwise direction.

Hence, the angular acceleration of the fan is 25 rad/sec² in clockwise direction.

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A fan initially rotating at 60 rad/sec clockwise accelerates and acquires an angular velocity of 110 rad/sec clockwise. If the angular acceleration of the fan is constant and it takes 2 sec to change its angular velocity, find the angular acceleration.

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3.A magnet held vertically, with its north pole down, is dropped along the axis of a closed solenoid placed vertically on a table. If the observer looks down from the top,

4.Draw the plot of potential energy of a pair of nucleons as a function of their separation. Write two important conclusions that can be drawn from this plot.

5.An electron is revolving around a proton in a circular orbit of radius $r$. Using classical physics, prove that the ratio of value of the angular momentum and the value of magnetic moment of electron revolving in the orbit is a constant.

6.Find the ratio $\dfrac{\lambda_\alpha}{\lambda_p}$ of the de Broglie wavelength $\lambda_\alpha$ associated with an alpha particle to the de Broglie wavelength $\lambda_p$ associated with a proton if both are moving with the same velocity.

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