Download App

4.1 , newtons laws of motion — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics4.1 , newtons laws of motion1 Mark
MCQ
Two blocks are connected by $a$ spring. The combination is suspended, at rest, from a string attatched to the ceiling, as shown in the figure. The string breaks suddenly. Immediately after the string breaks, what is the initial downward acceleration of the upper block of mass $2m$ ?
  • A
    $0$
  • ✓
    $3g/2$
  • C
    $g$
  • D
    $2g$
✓

Answer

Correct option: B.
$3g/2$
b
Let $a$ is the initial downward acceleration of the upper block of mass $2 \mathrm{m}$. before breaking of string, $T=2 m g+k x$ and $k x=m q$

Now, after the string is cut, the forces on the $2 \mathrm{m}$ block are$:$

the equation of motion of the mass $2 m$ is, $2 m a=(2 m+m) g$

$\therefore a=\frac{3 g}{2}$

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 "M.C.Q (1 Marks)" from 4.1 , newtons laws of motion→4.1 , newtons laws of motion — all question types→Physics STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

A p-type semiconductor is:
  1. Positively charged.
  2. Negatively charged.
  3. Uncharged.
  4. Uncharged at 0K but charged at higher ternperatures.
→
Which of the following statements is true regarding the molecular kinetic theory of gases?
→
The initial velocity of a particle moving along $x$-axis is $u$ (at $t=0$ and $x=0$ ) and its acceleration $a$ is given by $a=k x$. Which of the following equation is correct between its velocity $(v)$ and position $(x)$ ?
→
In the figure shown, a small ball hits obliquely a smooth and horizontal surface with speed $u$ whose $x$ and $y$ components are indicated. If the coefficient of restitution is $\frac{1}{2}$, then its $x$ and $y$ components $v_x$ and $v_y$ just after collision are respectively
→
The pressure that has to be applied to the ends of a steel wire of length $10\ cm$ to keep its length constant when its temperature is raised by $100^o C$ is: (For steel Young's modulus is $2 \times 10^{11}$ $Nm^{-1}$ and coefficient of thermal expansion is $1.1 \times 10^{-5}$ $K^{-1}$ )
→
Particle is dropped from the height of $20\,\,m$ from horizontal ground. There is wind blowing due to which horizontal acceleration of the particle becomes $6 ms^{^{-2}}$. Find the horizontal displacement of the particle till it reaches ground.  ........ $m$
→
Mark the correct statement

$(i)$ Escape velocity does not depend on mass of body

$(ii)$ If total energy of a satellite becomes positive, it escapes from earth

$(iii)$ Orbit of geostationary orbit is called parking orbit

→
From a building two balls $A$ and $B$ are thrown such that $A$ is thrown upwards and $B$ downwards (both vertically). If $v_{A}$ and $v_{B}$ are their respective velocities on reaching the ground, then
→
Certain substance emits only the wavelengths ${\lambda _1},\;{\lambda _2},\;{\lambda _3}$ and ${\lambda _4}$ when it is at a high temperature. When this substance is at a colder temperature, it will absorb only the following wavelengths
→
The plots of intensity versus wavelength for three black bodies at temperatures $T_1, T_2$ and $T_3$ respectively are as shown. Their temperature are such that
→