One end of a string of length $l$ is connected to a particle of mass $m$ and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed $v$ the net force on the particle (directed towards the centre) is :
$(i) \;T,$ $(ii)\; T-\frac{m v^{2}}{l},$ $(iii)\;T+\frac{m v^{2}}{l},$ $(iv) \;0$
$T$ is the tension in the string. [Choose the correct alternative].
$(i)$ $T$ When a particle connected to a string revolves in a circular path around a centre, the centripetal force is provided by the tension produced in the string. Hence, in the given case, the net force on the particle is the tension $T$, i.e.,
$F=T=\frac{m v^{2}}{l}$
Where $F$ is the net force acting on the particle.
A block of mass $M$ is pulled along a horizontal frictionless surface by a rope of mass $M / 2$. If a force $2 Mg$ is applied at one end of the rope, the force which the rope exerts on the block is -
See Figure given below. A mass of $6 \;kg$ is suspended by a rope of length $2 \;m$ from the ceiling. A force of $50\; N$ in the horizontal direction is applied at the midpoint $P$ of the rope, as shown. What is the angle the rope makes with the vertical in equilibrium ? (Take $g = 10 \;m s^{-2}$). Neglect the mass of the rope.
A smooth cylinder of mass $m$ and radius $R$ is resting on two corner edges $A$ and $B$ as shown in fig. The relation between normal reaction at the edges $A$ and $B$ is
Two equal heavy spheres, each of radius $r$, are in equilibrium within a smooth cup of radius $3 r$. The ratio of reaction between the cup and one sphere and that between the two sphere is
Give the magnitude and direction of the net force acting on
$(a)$ a drop of rain falling down with a constant speed,
$(b)$ a cork of mass $10\; g$ floating on water,
$(c)$ a kite skillfully held stationary in the sky,
$(d)$ a car moving with a constant velocity of $30\; km/h$ on a rough road,
$(e)$ a high-speed electron in space far from all material objects, and free of electric and magnetic fields.