A disc with a flat small bottom beaker placed on it at a distance $R$ from its center is revolving about an axis passing through the center and perpendicular to its plane with an angular velocity $\omega$. The coefficient of static friction between the bottom of the beaker and the surface of the disc is $\mu$. The beaker will revolve with the disc if
$R \leq \frac{\mu g}{2 \omega^{2}}$
$R \leq \frac{\mu g }{\omega^{2}}$
$R \geq \frac{\mu g}{2 \omega^{2}}$
$R \geq \frac{\mu g }{\omega^{2}}$
A modern grand-prix racing car of mass $m$ is travelling on a flat track in a circular arc of radius $R$ with a speed $v$. If the coefficient of static friction between the tyres and the track is $\mu_{s},$ then the magnitude of negative lift $F_{L}$ acting downwards on the car is
(Assume forces on the four tyres are identical and $g =$ acceleration due to gravity)
A mass is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity ${\omega _0}$. If the length of the string and angular velocity are doubled, the tension in the string which was initially ${T_0}$ is now
A cyclist is travelling with velocity $v$ on a curved road of radius $R$. The angle $\theta$ through which the cyclist leans inwards is given by
A car is moving on a circular path and takes a turn. If ${R_1}$ and ${R_2}$ be the reactions on the inner and outer wheels respectively, then
A car of $800 \mathrm{~kg}$ is taking turn on a banked road of radius $300 \mathrm{~m}$ and angle of banking $30^{\circ}$. If coefficient of static friction is $0.2$ then the maximum speed with which car can negotiate the turn safely : $\left(\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2, \sqrt{3}=1.73\right)$