MCQ
A heavy solid sphere is thrown on a horizontal rough surface with initial velocity $u$ without rolling. What will be its speed, when it starts pure rolling motion?
- A$\frac{3 u}{5}$
- B$\frac{2 u}{5}$
- ✓$\frac{5 u}{7}$
- D$\frac{2 u}{7}$
✓
Answer
Correct option: C.
$\frac{5 u}{7}$
c
(c)
(c)
Using angular momentum conservation
$m u r=m v r+\frac{2}{5} m r^2\left(\frac{v}{r}\right)$
$u=7 \frac{v}{5}$
$v=\frac{5 u}{7}$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A double convex lens has power $P$ and same radii of curvature $R$ of both the surfaces. The radius of curvature of a surface of a plano-convex lens made of the same material with power $1.5P$ is ......$R$
→Which of the following physical quantities have the same dimensions?
The intensity ratio of two waves is $1 : 16$. The ratio of their amplitudes is
→Find magnetic field at point $P$ in given diagram.
→In a photoelectric experiment, increasing the intensity of incident light :
A body of mass $8\,kg$ is moved by a force $F = 3x\,N,$ where $x$ is the distance covered. Initial position is $x = 2\,m$ and the final position is $x = 10\,m$. The initial speed is $0.0\,m/s.$ The final speed is ........... $m/s$
→If $50$ Vernier divisions are equal to $49$ main scale divisions of a travelling microscope and one smallest reading of main scale is $0.5 \mathrm{~mm}$, the Vernier constant of travelling microscope is:
→In a $PNP$ transistor working as a common-base amplifier, current gain is $0.96$ and emitter current is $7.2\, mA$. The base current is.....$mA$
→A ball is thrown vertically upwards from the top of a tower with a velocity $u$. This ball reaches the ground level with a velocity $4\,u$. The height of the tower is
→A battery of $e.m.f.$ $10\, V$ is connected to resistance as shown in figure. The potential difference ${V_A} - {V_B}$ between the points $A$ and $B$ is .................... $V$
→