If $\overrightarrow{a}=3\hat{\mathrm{i}}+4\hat{\mathrm{j}}$ and $\overrightarrow{b}=4\hat{\mathrm{i}}-3\hat{\mathrm{j}}$, then 

Angular momentum of a particle $P$ about point $O$ is $\overrightarrow{L}=\overrightarrow{O}P\times m\overrightarrow{v}$,

where $m$ is the mass of particle and $v$ is its velocity. $A$ particle of mass $2 \mathrm{kg}$ is moving with speed $10 \mathrm{m} {\mathrm{s}}^{-1}$ as shown in the figure. Which of the following statements is/are correct.

The magnetic force on a moving charge is $\overrightarrow{F}=q\overrightarrow{v}\times \overrightarrow{B}$. Here $q$ is electric charge on particle, $v$ is velocity of the particle and $B$ is magnetic field.

A charged particle of charge $1 C$ moving with a velocity $\left(\hat{\mathrm{i}}+\hat{\mathrm{j}}-\hat{\mathrm{k}}\right) \mathrm{m} {\mathrm{s}}^{-1}$ in a magnetic field $B=\left(2\hat{\mathrm{i}}-\hat{\mathrm{j}}+4\hat{\mathrm{k}}\right) T$.

Choose the correct option(s).

According to Newton's second law of motion, the resultant force on a particle is in the direction of acceleration of the particle.

Two forces $F_1$ and $F_2$ are acting on a particle as shown in the figure. The acceleration of the particle is along $x$-axis. Find the value of $F_1$ (in newton).