Download App

Rotational Mechanics — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsRotational Mechanics3 Marks
Question
Suppose the platform with the kid in the previous problem is rotating in anticlockwise direction at an angular speed $\omega.$ The kid starts walking along the rim with a speed v relative to the platform also in the anticlockwise direction. Find the new angular speed of the platform.
✓

Answer

From a inertial frame of reference when we see the (man wheel) system, we can find that the wheel moving at a speed of $\omega$ and the man with $\Big(\omega+\frac{\text{V}}{\text{R}}\Big)$ after the man has started walking. $(\omega'=$ angular velocity after walking, $\omega=$ angular velocity of the wheel before walking$).$

Since $\sum\text{l}=0$

Extended torque = 0

Therefore, $(1+\text{MR}^2)\omega=\text{l}\omega'+\text{mR}^2\Big(\omega'+\frac{\text{V}}{\text{R}}\Big)$

$\Rightarrow(1+\text{MR}^2)\omega=\text{l}\omega'+\text{mR}^2\omega'+\text{mVR}$

$\Rightarrow\omega'=\omega-\frac{\text{mVR}}{(1+\text{mR}^2)}.$

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 Rotational Mechanics→Rotational Mechanics — all question types→Physics STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

A ball of mass 0.50kg moving at a speed of 5.0m/s collides with another ball of mass 1.0kg. After the collision the balls stick together and remain motionless. What was the velocity of the 1.0kg block before the collision?
→
An object of size 3.0 cm is placed 14 cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved further away from the lens?
→
A uniform magnetic field of magnitude 0.20T exists in space from east to west. With what speed should a particle of mass 0.010g and with charge 1.0 × 10-5C be projected from south to north so that it moves with uniform velocity?
→
(I) Identify the circuit elements X and Y as shown in the given block diagram and draw the output waveforms of X and Y.

Image

(II) If the centre tapping is shifted towards Diode D1 as shown in the diagram, draw the output waveform of the given circuit.

Image
→
A myopic person has been using spectacles of power –1.0 dioptre for distant vision. During old age he also needs to use separate reading glass of power + 2.0 dioptres. Explain what may have happened.
→
A regular hexagon of side 10 cm has a charge 5 µC at each of its vertices. Calculate the potential at the centre of the hexagon.
→
A person sitting on the top of a tall building is dropping balls at regular intervals of one second. Find the positions of the 3rd, 4th and 5th ball when the 6th ball is being dropped.
→
Two heated wires of the same dimensions are first connected in series and then in parallel to a source of supply. What will be the ratio of heat produced in the two cases?
→
What is the de Broglie wavelength associated with (a) an electron moving with a speed of $5.4 \times 10^6 m / s$, and (b) a ball of mass $150 g$ travelling at $30.0 m / s$ ?
→
A concrete slab has a length of 10m on a winter night when the temperature is 0°C. Find the length of the slab on a summer day when the temperature is 35­°C. The coefficient of linear expansion of concrete is 1.0 × 10-5­°C-1.
→