If $\overrightarrow{a}+\overrightarrow{b}+\overrightarrow{c}=\overrightarrow{0}$ and $|\overrightarrow{a}|=3, |\overrightarrow{b}|=4$ and $|\overrightarrow{c}|=\sqrt{37}$,then the angle between $\overrightarrow{a}$ and $\overrightarrow{b}$ is:

The minimum value of $27 \tan ^2 \theta + 3 \cot ^2 \theta$ is

Three processes form a thermodynamic cycle as shown on the $P-V$ diagram for an ideal gas. Process $1 \to 2$ takes place at a constant temperature $(300\,K)$. Process $2 \to 3$ takes place at a constant volume. During this process,$40\,J$ of heat leaves the system. Process $3 \to 1$ is adiabatic and the temperature $T_3$ is $275\,K$. The work done by the gas during the process $3 \to 1$ is...... $J$.

According to the kinetic theory of gases,when two molecules of gas collide with each other,then:

The midpoint of the chord $4x - 3y = 5$ of the hyperbola $2x^2 - 3y^2 = 12$ is

How many main types of muscles are there?