Question
A coin is placed on a horizontal platform which undergoes vertical simple harmonic motion of angular frequency $\omega $. The amplitude of oscillation is gradually increased. The coin will leave contact with the platform for the first time
✓
Answer
For block $A$ to move in $SHM.$
$\mathrm{mg}-\mathrm{N}=\mathrm{m} \omega^{2} \mathrm{x}$
where $x$ is the distance from mean position
For block to leave contact $\mathrm{N}=0$
$\Rightarrow m g=m \omega^{2} x \Rightarrow x=\frac{g}{\omega^{2}}$
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 flywheel rotates about an axis. Due to friction at the axis, it experiences an angular retardation proportional to its angular velocity. If its angular velocity falls to half while it makes $n$ rotations, how many more rotations will it make before coming to rest?
→The energy liberated per nuclear fission is $200 \;MeV$. If $10^{20}$ fissions occur per/second the amount of power produced will be
→An electron collides with a free molecule initially in its ground state. The collision leaves the molecule in an excited state that is metastable and does not decay to the ground state by radiation. Let $K$ be the sum of the initial kinetic energies of the electron and the molecule and $p$ be the sum of their initial momenta. Let $K^{\prime}$ and $p ^{\prime}$ represent the same physical quantities after the collision. Then,
→When temperature increases, the frequency of a tuning fork
Following figure shows four situations in which positive and negative charges moves horizontally through a region and gives the rate at which each charge moves. Rank the situations according to the effective current through the region greatest first
Assertion : A $p-n$ junction with reverse bias can be used as a photo-diode to measure light intensity.
→Reason: In a reverse bias condition the current is small but is more sensitive to changes in incident light intensity
A projectile is fired at an angle of $45^o $ with the horizontal . Elevation angle of the projectile at its highest point as seen from the point of projection, is
→A transformer consisting of $300$ turns in the primary and $150$ turns in the secondary gives output power of $2.2\, kW$. If the current in the secondary coils is $10\, A$, then the input voltage and current in the primary coil are
→An electrical bulb rated $220\,V , 100\,W$, is connected in series with another bulb rated $220\,V$, $60\,W$.If the voltage across combination is $220\,V$, the power consumed by the $100\,W$ bulb will be about $........... W$
→A particle starts from rest, accelerates at $2 \,ms^{-2}$ for $10\,s$ and then goes for constant speed for $30\,s$ and then decelerates at $ 4\, ms^{-2}$ till it stops. What is the distance travelled by it.........$m$
→