Which one of the following is most effective in causing the coagulation of an $As_2S_3$ sol?

$A$ man of $50\, kg$ mass is standing in a gravity-free space at a height of $10\, m$ above the floor. He throws a stone of $0.5\, kg$ mass downwards with a speed of $2\, m/s$. When the stone reaches the floor,the distance of the man above the floor will be ........ $m.$

Which of the following is not a polymer?

The force required to move a body up a rough inclined plane is double the force required to prevent the body from sliding down the plane. The coefficient of friction,when the angle of inclination of the plane is $60^{\circ}$,is

$A$ physical quantity $X$ is given by $X = \frac{2 k^3 \ell^2}{m \sqrt{n}}$. The percentage errors in the measurement of $k, \ell, m,$ and $n$ are $1\%, 2\%, 3\%,$ and $4\%$ respectively. The percentage uncertainty in the value of $X$ is: (in $\%$)

The line joining the points $A(2,0)$ and $B(3,1)$ is rotated through an angle of $45^{\circ}$ about $A$ in the anti-clockwise direction. Find the coordinates of $B$ in the new position.