MCQ
A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly
  • A
    Its speed of rotation increases
  • Its speed of rotation decreases
  • C
    Its speed of rotation remains same
  • D
    Its speed of rotation increases because its moment of inertia increases

Answer

Correct option: B.
Its speed of rotation decreases
b
When a metallic rod is heated it expands. Its moment of inertia $(1)$ about a perpendicular bisector increases. Ac cording to law of conservation of angular momentum, its angular speed ( $\omega$ ) decreases, since $\omega \propto 1 / l$ (ac cording to law of conservation of angular momentum).

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

Similar questions

Acylindrical vessel open at the top is $20$ $cm$ high and $10$ $cm$ in diameter.Acircular hole whose cross-sectional area $1$ $cm^2$ is cut at the centre of the bottom of the vessel. Water flows from a tube above it into the vessel at the rate $100$ $cm^3s^{^{-1}}$. The height of water in the vessel under steady state is ....... $cm$ (Take $g=1000 $ $ cms^{^{-2}})$
Standing waves are produced in a $10 \;m$ long stretched string. If the string vibrates in $5$ segments and the wave velocity is $20\; m/s$, the frequency is ... $Hz$
Which of the following graphs best represents the motion of a raindrop?
A student in the laboratory measures thickness of a wire using screw gauge. The readings are $1.22\,mm , 1.23\,mm , 1.19\,mm$ and $1.20\,mm$. The percentage error is $\frac{ x }{121} \%$. The value of $x$ is ..............
A pendulum consists of a bob of mass $m=0.1 kg$ and a massless inextensible string of length $L=1.0 m$. It is suspended from a fixed point at height $H=0.9 m$ above a frictionless horizontal floor. Initially, the bob of the pendulum is lying on the floor at rest vertically below the point of suspension. A horizontal impulse $P=0.2 kg - m / s$ is imparted to the bob at some instant. After the bob slides for some distance, the string becomes taut and the bob lifts off the floor. The magnitude of the angular momentum of the pendulum about the point of suspension just before the bob lifts off is $J kg - m ^2 / s$. The kinetic energy of the pendulum just after the lift-off is $K$ Joules.

($1$) The value of $J$ is. . . . . .

($2$) The value of $K$ is. . . . .

Give the answers of the questions ($1$) and ($2$)

In the figure shown the velocity of different blocks is shown. The velocity of $C$ is $.........\,m/s$
Which one of the following graph for a body moving along a straight line is possible?
From the top of a tower, a particle is thrown vertically downwards with a velocity of $10\; m/s$. The ratio of the distances, covered by it in the $3^{rd}$ and $2^{nd}$ seconds of the motion is (Take $g = 10\,m/{s^2}$)
A particle moves on a straight line with a uniform velocity. Its angular momentum:
A rectangular block of mass $m$ and area of cross section $A$ floats in a liquid of density $\rho$ If it is given a small vertical displacement from equilibrium, it undergoes oscillations with a time period $T,$ then: