Force acting on a particle is given by $\overrightarrow{F}=\overrightarrow{a}\times \overrightarrow{P}$, where ,$\overrightarrow{a}$   is a constant vector and  $\overrightarrow{P}$ is linear momentum of the particle. Choose the correct option(s):  

$\overrightarrow{F}=\overrightarrow{a}\times \overrightarrow{P}$

$\overrightarrow{F}$  is always perpendicular to   $\overrightarrow{P}$
So , It can’t change speed hence KE is also constant.
$\overrightarrow{P}$ will change its direction. 
$\left|\overrightarrow{F}\right|$ will be constant; so particle will move on a circular trajectory.