Answer:
So we are applying 80 N on the block, 20kg in mass and it moves with the acceleration of 2.5 m/s/s
so we can find the force being applied on the block
F = ma
F = 20 X 2.5
F = 50 N
So only 50 N of the 80 N is being applied on the block.
Hence, the remaining 80-50 = 30 N force is being used to overcome friction
Force of Kinetic Friction = 30 N
Now, in this case the Normal Force will be equal to the Force applied by gravity(Mg)
So, Normal Force = 200 N
Coefficient of kinetic friction = Force of Kinetic Friction / Normal Force
Coefficient of kinetic friction = 30 / 200
Coefficient of Kinetic Friction = 0.15