After 10sec, 21mv2=81mv02
⇒v=2v0=5ms−1
Acceleration, a=−mkv2
⇒dtdv=−mkv2
⇒∫105v2dv=−mk∫010dt
−51+101=10−2−k×10
k=10−4kgm−1
A body of mass m=10^-2 kg is moving in a medium and experiences a frictional force F=-kv^2 . Its initial speed is v_0=10ms^-1. After 10s its kinetic…
JEE Main 2017 — Physics Mechanics
2017mcqhard
A body of mass m=10−2kg is moving in a medium and experiences a frictional force F=−kv2. Its initial speed is v0=10ms−1. After 10s its kinetic energy is 81mv02, then value of k will be:-
Official previous-year question
Held on 2 Apr 2017 · Verified 6 Jul 2026.
Options
- A
10−1kgm−1s−1
- B
10−3kgm−1
- C
10−3kgs−1
- D
10−4kgm−1
Did you get this right?
Sign in to track your attempts and accuracy.
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.
JEE Main Mechanics in other years
More JEE Main Mechanics questions
If $\epsilon, E$ and $t$ represent the free space permittivity, electric field and time respectively, then the unit of $\frac{\epsilon E}{t}$ will be :
2026easy
When a part of a straight capillary tube is placed vertically in a liquid, the liquid raises upto certain height $h$. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by $1 \%$ each, then the height of the liquid in the tube will change by $\%$.
2026medium
The velocity of a particle is given as $\vec{v} = -x\hat{i} + 2y\hat{j} - z\hat{k}$ m/s. The magnitude of acceleration at point $(1, 2, 4)$ is _______ m/s$^2$.
2026hard
Suppose there is a uniform circular disc of mass $M \mathrm{~kg}$ and radius $r \mathrm{~m}$ shown in figure. The shaded regions are cut out from the disc. The moment of inertia of the remainder about the axis $A$ of the disc is given by $\frac{x}{256} M r^{2}$. The value of $x$ is $\_\_\_\_$. 
2026hard
A soap bubble of surface tension $0.04 \mathrm{~N} / \mathrm{m}$ is blown to a diameter of 7 cm. If $(15000-x) \mu \mathrm{J}$ of work is done in blowing it further to make its diameter 14 cm, then the value of $x$ is $\_\_\_\_$. ($\pi=22 / 7$)
2026medium
Other Physics topics for JEE Main
Keep practicing Mechanics
Work through every JEE Main Mechanics PYQ, year by year.