Final answer:
The magnitude of the normal force acting on block A placed on the smooth triangular surface with a 30° incline is approximately 24.5 N.
Step-by-step explanation:
The normal force acting on a block on an inclined plane can be determined using the formula: N = m * g * cos(theta), where N is the normal force, m is the mass of the block, g is the acceleration due to gravity, and theta is the angle of the incline. In this case, the mass of Block A is 5 kg and the angle of the incline is 30°.
Plugging in the values, we have: N = 5 kg * 9.8 m/s² * cos(30°)
Using the formula for cosine of a special angle, cos(30°) = sqrt(3)/2, we can calculate the normal force:
N = 5 kg * 9.8 m/s² * sqrt(3)/2 = 24.5 N
Therefore, the magnitude of the normal force acting on Block A is approximately 24.5 N.