Download App

Systems of Particles and Rotational Motion — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysicsSystems of Particles and Rotational Motion3 Marks
Question
A body rotating at 20rad/s is acted upon by a constant torque providing it a deceleration of 2rad/s2. At what time will the body have kinetic energy same as the initial value if the torque continues to act?
✓

Answer

Initial angular velocity = 20rad/s
Therefore $\alpha=2\text{rad/s}^2$
$\Rightarrow\text{t}_1=\frac{\omega_2}{\alpha_1}=\frac{20}{2}=10\text{sec}$
Therefore 10sec it will come to rest.
Since the same torque is continues to act on the body it will produce same angular acceleration and since the initial kinetic energy = the kinetic energy at a instant.
So initial angular velocity = angular velocity at that instant
Therefore time require to come to that angular velocity,
$\Rightarrow\text{t}_2=\frac{\omega}{\alpha_2}=\frac{20}{2}=10\text{sec}$
therefore time required = t1 + t2 = 20sec.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Systems of Particles and Rotational Motion→Systems of Particles and Rotational Motion — all question types→Physics STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

The nearest star to our solar system is 4.29 light years away. How much is this distance in terms of parsecs? How much parallax would this star (named Alpha Centauri) show when viewed from two locations of the Earth six months apart in its orbit around the Sun?
→
If the Earth were to suddenly contract to $\frac{1}{\text{n}}^{\text{th}}$ of its present radius, without any change in its mass, then what will be the effect on the duration of the day?
→
A person aims a gun at a bird from a point at a horizontal distance of 100m. If the gun can impart a speed of 500ms-1 to the bullet, at what height above the bird must he aim his gun in order to hit it?
→
A stone is dropped from the top of a cliff and is found to ravel 44.1 m diving the last second before it reaches the ground. What is the height of the cliff? $g =9.8 m / s ^2$.
→
Explain the difference between beats and interfrence.
→
Find the temperature at which the average thermal kinetic energy is equal to the energy needed to take a hydrogen atom from its ground state to n = 3 state. Hydrogen can now emit red light of wavelength 653.1nm. Because of Maxwellian distribution of speeds, a hydrogen sample emits red light at temperatures much lower than that obtained from this problem. Assume that hydrogen molecules dissociate into atoms.
→
The second overtone of an open pipe has the same frequency as the first overtone of a closed pipe 2m long. What is the length of the open pipe?
→
A physical quantity P is related to four observables a, b, c and d as follows:
$\text{P}=\text{a}^3\text{b}^3/\big(\sqrt{\text{c}}\text{ d}\big)$
The percentage errors of measurement in a, b, c and d are 1%, 3%, 4% and 2%, respectively. What is the percentage error in the quantity P ? If the value of P calculated using the above relation turns out to be 3.763, to what value should you round off the result ?
→
A black body at 2000K emits maximum energy at a wavelength of $1.56\mu\text{m}.$ At what temperature will it emit maximum energy at a wavelength of $1.8\mu\text{m}\ ?$
→
A vessel contains 1.60g of oxygen and 2.80g of nitrogen. The temperature is maintained at 300K and the volume of the vessel is 0.166m3. Find the pressure of the mixture.
→