MCQ
A particle is projected upwards. The times corresponding to height $h$ while ascending and while descending are $t‌‌_1$ and $t_2$ respectively. The velocity of projection will be
  • A
    $g{t_1}$
  • B
    $g{t_2}$
  • C
    $g\;\left( {{t_1} + {t_2}} \right)$
  • $\frac{{g\left( {{t_1} + {t_2}} \right)}}{2}$

Answer

Correct option: D.
$\frac{{g\left( {{t_1} + {t_2}} \right)}}{2}$
d
(d) If ${t_1}$ and ${t_2}$ are time of ascent and descent respectively then time of flight $T = {t_1} + {t_2} = \frac{{2u}}{g}$

==> $u = \frac{{g({t_1} + {t_2})}}{2}$

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

Similar questions

A $2 \,kg$ block is lying on a smooth table which is connected by a body of mass $1\, kg$ by a string which passes through a pulley. The $1\, kg$ mass is hanging vertically. The acceleration of block and tension in the string will be
A particle executes simple harmonic oscillation with an amplitude $a.$ The period of oscillation is $T.$ The minimum time taken by the particle to travel half of the amplitude from the equilibrium position is 
Two bodies are thrown up at angles of $45^o $ and $60^o $, respectively, with the horizontal. If both bodies attain same vertical height, then the ratio of velocities with which these are thrown is
The figure shows the velocity and the acceleration of a point like body at the initial moment of its motion. The direction and the absolute value of the acceleration remain constant. Find the time when the speed becomes minimum.........$s$ (Given : $a = 4\, m/s^2, v_0 = 40\, m/s, \phi =143^o$)
Two vessels of different materials are similar in size in every respect. The same quantity of ice filled in them gets melted in $20$ minutes and $30$ minutes. The ratio of their thermal conductivities will be
A metallic block of density $5\,gm \,cm^{-3}$ and having dimensions $5 cm × 5 cm × 5 cm$ is weighed in water. Its apparent weight will be
Five moles of helium are mixed with two moles of hydrogen to form a mixture. Take molar mass of helium $M_1=4\ g$ and that of hydrogen $M_2=2\ g$ If the internal energy of He sample of $100\,\,J$ and that of the hydrogen sample is $200\,\,J$, then the internal energy of the mixture is ..... $J$
Two uniform circular discs are rotating independently in the same direction around their common axis passing through their centres. The moment of inertia and angular velocity of the first disc are $0.1 \;kg - m ^{2}$ and $10\; rad \,s^{-1}$ respectively while those for the second one are $0.2 \;kg - m ^{2}$ and $5\; rad \,s ^{-1}$ respectively. At some instant they get stuck together and start rotating as a single system about their common axis with some angular speed. The Kinetic energy of the combined system is ...........$J$
The time after which they are closet to each other:
A uniform sphere of mass $500\; g$ rolls without slipping on a plane horizontal surface with its centre moving at a speed of $5.00\; \mathrm{cm} / \mathrm{s}$. Its kinetic energy is