MCQ
Two particles $A$ and $B$ initially at rest, move towards each other, under mutual force of attraction. At an instance when the speed of $A$ is $v$ and speed of $B$ is $2v,$ the speed of centre of mass $(CM)$ is:
- ✓Zero
- B$v$
- C$2.5v$
- D$4v$
✓
Answer
Correct option: A.
Zero
As initially both the particles were at rest therefore velocity of centre of mass was zero and there is no external force on the system so speed of centre of mass remains constant i.e., it should be equal to zero.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A particle is moving with constant acceleration $'a'.$ Following graph shows $v^{2}$ versus $x$ (displacement) plot. The acceleration of the particle is $......{m} / {s}^{2}$
→If force $(F)$, length $(L) $ and time $(T)$ are assumed to be fundamental units, then the dimensional formula of the mass will be
→The process on an ideal gas, shown in figure. is:
Figure shows the displacement of a particle going along the $X-$axis as a function of time. The force acting on the particle is zero in the region:
→
- $AB$
- $BC$
- $CD$
- $DE$
We are able to squeeze snow and make balls out of it because of
Oxygen and hydrogen are at the same tempeature T. The kinetic energy of the oxygen molecule is equal to the kinetic energy of the hydrogen molecule.
A ball rolls without slipping. The radius of gyration of the ball about an axis passing through its centre of mass $K$. If radius of the ball be $R$, then the fraction of total energy associated with its rotational energy will be
→For the system shown in figure, $m_1>m_2>m_3 >m_4$ . Initially, the system is at rest in equilibrium condition. If the string joining $m_4$ and ground is cut, then just after the string is cut :
→Statement $I$ $m_1$ ,$m_2$ ,$m_3$ remain stationary.
Statement $II$ The value of acceleration of all the $4$ blocks can be determined.
Statement $III$ Only $m_4$ remains stationary.
Statement $IV$ Only $m_4$ accelerates.
Statement $V$ All the four blocks remain stationary.
Now, choose the correct option.
The radius of a pipe of unequal section varies from $r_1$ to $r_2$. If the velocity of flow of fluid in the pipe changes from $v_1$ to $v_2$ then $\frac{v_1}{v_2}$ is equal to :
→At ${27^o}C$ a gas is suddenly compressed such that its pressure becomes $\frac{1}{8}th$ of original pressure. Temperature of the gas will be $(\gamma = 5/3)$
→