Given that
Mass of wooden block m = 2 kg
Mass of iron cylinder M = 25 kg
Acceleration of the block and cylinder a = 0.1 m/s^2
Acceleration due to gravity g = 10 m/s^2
a)
The earth's gravitational pulling force and the normal force R exerted by the block's floor are both acting on the block on the floor.

According to the newton's third law of motion
Action: the block's force on the floor
Reaction: the floor's force on the block
R=mg
R=2*10
R=20N
Thus, force exerted on the floor by the block R = 20 N
b)

Total mass of the system = mass of the block + mass of the cylinder
m_s = m + M = 2 kg + 25 kg = 27 kg
Forces acting on the system
(i) System is accelerating downwards
(ii) Normal force acting upwards
(ii) Weight of the system acting downwards
\therefore Action force F = m_s g - R
m_s a = m_s g - R
R = 27 *10 - 27 *(0.1)
R = 267.3
Hence, the action of the system on the floor R = 267.3 N