Answer:
The magnitude of the kinetic frictional force is 25 N.
Step-by-step explanation:
Kinetic frictional force :
A force which is act between moving surface it is called kinetic frictional force.
When an object moves on the surface then it experienced a force in the opposite direction of its movement.
The friction force always acts opposite of the actual force.
The kinetic friction force is defined in mathematically terms

Where, N = normal force
= friction coefficient
According to figure,
Hence, The magnitude of the kinetic frictional force is 25 N.