Find the acceleration of the block of mass M = 5.26 kg in the figure below. (Take m = 4.06 kg.)

To find the acceleration of the block, we need to analyze the forces acting on it.

Looking at the figure provided, we see that there are three forces acting on the block:
1. The force of gravity (weight) acting vertically downward with a magnitude of mg, where g is the acceleration due to gravity (approximately 9.8 m/s^2).
2. The normal force acting vertically upward perpendicular to the inclined plane. This force counters the vertical component of the weight and is equal in magnitude but opposite in direction to the vertical component of the weight, which is given by mgcos(theta), where theta is the angle of the incline.
3. The force of friction acting horizontally in the opposite direction of motion. This force opposes the motion of the block and its magnitude is given by the coefficient of friction (mu) multiplied by the normal force, which is mugsin(theta).

Since the block is on an inclined plane, we can resolve the weight into two components: one perpendicular to the incline and one parallel to it. The component parallel to the incline is mgsin(theta), and this is the force responsible for accelerating the block.

Therefore, the net force acting on the block is the force parallel to the incline, which is mgsin(theta), minus the force of friction, which is mugsin(theta). The net force can be written as ma, where a is the acceleration of the block.

Thus, we have the equation:
mgsin(theta) - mugsin(theta) = ma

Now, we can substitute the given values into the equation:
m = 5.26 kg (mass of the block)
g = 9.8 m/s^2 (acceleration due to gravity)
mu = coefficient of friction
theta = angle of incline
a = unknown (acceleration)

By rearranging the equation and solving for a, we can find the acceleration of the block.