The equation of the tangent at $(-4, -4)$ on the curve $x^2 = -4y$ is

$A$ ball is thrown upward with an initial velocity $V_0$ from the surface of the earth. The motion of the ball is affected by a drag force equal to $m \gamma v^2$ (where $m$ is the mass of the ball,$v$ is its instantaneous velocity,and $\gamma$ is a constant). The time taken by the ball to rise to its zenith is:

The number of points in $(-\infty, \infty)$ for which $x^2 - x \sin x - \cos x = 0$ is

Which structure acts as the pacemaker of the heart?

$A$ monoatomic ideal gas initially at temperature $T_1$ is enclosed in a cylinder fitted with a massless,frictionless piston. By releasing the piston suddenly,the gas is allowed to expand adiabatically to a temperature $T_2$. If $L_1$ and $L_2$ are the lengths of the gas columns before and after expansion respectively,then $\frac{T_2}{T_1}$ is

Which of the following is the simplest amino acid?