Which one of the following is the molecular formula of a tertiary amine?

From the top of a tower of height $40 \ m$,a ball is projected upwards with a speed of $20 \ m/s$ at an angle $30^{\circ}$ to the horizontal. The ball will hit the ground in time ......... $\sec$ (Take $g = 10 \ m/s^2$)

Two stones of masses $m$ and $3m$ are whirled in horizontal circles,the heavier one in a radius $\left(\frac{r}{3}\right)$ and the lighter one in a radius $r$. The tangential speed of the lighter stone is '$n$' times the value of the heavier stone. When the magnitude of the centripetal force becomes equal,the value of $n$ is:

Which of the following is an incorrect pair?

$A$ space $2.5 \ cm$ wide between two large plane surfaces is filled with oil. The force required to drag a very thin plate of area $0.5 \ m^2$ just midway between the surfaces at a speed of $0.5 \ m/s$ is $1 \ N$. The coefficient of viscosity in $kg/(m \cdot s)$ is:

Do you expect the carbon hydrides of the type $(C_{n}H_{2n+2})$ to act as 'Lewis' acid or base? Justify your answer.