How do i find the magnitude of the net force acting on the box

20 N

Explanation:

Newton's second Law of motion law states that If there is a external force acting on an object. Then the rate of change of momentum of  that object is directly proportional to the force acting on its.

Due to momentum change of that object, momentum change. We can write the equation bellow this,

F = (mV-mU)/t

When m is constant we can write the above expression like this,

F = m (V-U)/t

There for

(V-U)/t  =  a ( Rate of change of velocity can be denoted as acceleration )

F = m× a

we can state this in mathematically,

a = F/m

in another representation

F = m*a

Net Force = mass*acceleration

                 = 10 * 2

                 = 20 N

object is subjected to a negative acceleration due to the friction.