A particle of mass 100 g is projected at time t = 0 with a speed 20… | JEE Main 2023 (29 Jan, Shift 2)

Q37JEE Main 2023 · 29 JAN · SHIFT 2Medium

Angular Momentum & its Conservation

A particle of mass 100 g is projected at time t = 0 with a speed 20 ms $-1$ at an angle 45 $^\circ$ to the horizontal as given in the figure. The magnitude of the angular momentum of the particle about the starting point at time t = 2s is found to be $\sqrt{\mathrm{K}}\text{ kg m}^{2}\text{/s}$ . The value of K is ___________. (Take g = 10 ms $-2$ )

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 800

For a projectile, $L$ about the launch point $=\frac12mg\,u_x t^2$ (only gravity gives torque).
$u_x=20\cos45^\circ=10\sqrt2$ m/s
$L=\frac12\times0.1\times10\times10\sqrt2\times2^2=20\sqrt2=\sqrt{800}$
So $K=800$ .

Report a mistake

More questions on Angular Momentum & its Conservation

A circular plate is rotating in horizontal plane, about an axis passing through its…JEE Main 2023 (11 Apr, Shift 2)
If the earth suddenly shrinks to 1/64 th of its original volume with its mass remaining…JEE Main 2023 (10 Apr, Shift 1)
A thin uniform circular disc of mass ' M ' and radius ' R ' is rotating with angular…MHT CET 2023 (12 May, Shift 1)
The position vector of 1 kg object is r = (3i - j)m and its velocity v = (3j + k)ms⁻¹…JEE Main 2022 (28 Jun, Shift 1)
A spherical shell of 1 kg mass and radius R is rolling with angular speed ω on horizontal…JEE Main 2022 (29 Jun, Shift 1)
A thin circular ring of mass M and radius R is rotating with a constant angular velocity…JEE Main 2022 (26 Jun, Shift 1)
A particle with position vector r has a linear momentum P. Which one of the following…MHT CET 2021 (22 Sep, Shift 2)
Angular momentum of a single particle moving with constant speed along circular path:JEE Main 2021 (31 Aug, Shift 1)

Angular Momentum & its Conservation question from JEE Main 2023 (29 Jan, Shift 2)

More questions on Angular Momentum & its Conservation