MCQ
From the top of a tower, a particle is thrown vertically downwards with a velocity of $10\; m/s$. The ratio of the distances, covered by it in the $3^{rd}$ and $2^{nd}$ seconds of the motion is (Take $g = 10\,m/{s^2}$)
  • A
    $5:7$
  • $7:5$
  • C
    $3:6$
  • D
    $6:3$

Answer

Correct option: B.
$7:5$
b
(b) ${S_{{3^{rd}}}} = 10 + \frac{{10}}{2}(2 \times 3 - 1) = 35\;m$

${S_{{2^{nd}}}} = 10 + \frac{{10}}{2}(2 \times 2 - 1) = 25\,m$

$\frac{{{S_{{3^{rd}}}}}}{{{S_{{2^{nd}}}}}} = \frac{7}{5}$

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

Similar questions

A rod $AB$ is free to rotate in a vertical plane about a horizontal axis through $A$ as shown in figure. It is slightly disturbed from rest in its position of unstable equilibrium and when it is next vertical the end $B$ collides with a fixed peg and rebounds. If the rod comes to instantaneous rest when $AB$ is horizontal (as shown in figure) then :-
A body is moving along a circular path. How much work is done by the centripetal force?
A ball projected from ground at an angle of $45^o$ just clears a wall in front. If point of projection is $4\,m$ from the foot of wall and ball strikes the ground at a distance of $6\,m$ on the other side of the wall, the height of the walI is  ........ $ m$
$Assertion$ : There is a stage when frictional force is not needed at all to provide the necessary centripetal force on a banked road.
$Reason$ : On a banked road, due to its inclination the vehicle tends to remain inwards without any chances of skidding.
A cylinder containing water, stands on a table of height $H$. A small hole is punched in the side of cylinder at its base. The stream of water strikes the ground at a horizontal distance $R$ from the table. Then the depth of water in the cylinder is ............
A train has just complicated a $U-$curve in a track which is a semicircle. The engine is at the forward end of the semi circular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency $200 Hz.$ Velocity of sound is $340 m/sec$. Then the apparent frequency as observed by a passenger in the middle of a train when the speed of the train is $30 m/sec$ is  ... $Hz$
A solid sphere of mass $500\ gm$ and radius $10\ cm$ rolls without slipping with the velocity $20\ cm/s$.  The total kinetic energy of the sphere will be  ........ $J$
A force of magnitude $50\, N$ acting along $\widehat i + \widehat j + \widehat k$, displaces a point mass from $(5, 9, 7)$ to $(4, 8, 6)$. The work done by this force during this displacement is :-
A bar magnet is released from rest along the axis of a very long, vertical copper tube. After some time the magnet:
A thin but rigid semicircular wire frame of radius $r$ is hinged at $O$ and can rotate in its own vertical plane. A smooth peg $P$ starts from $O$ and moves horizontally with constant speed $v_0$, lifting the frame upward as shown in figure.Find the angular velocity $\omega$ of the frame when its diameter makes an angle of $60^{\circ}$ with the vertical :