Efficiency is defined as the ratio of useful work output to total work input. In this case, the useful work output is the work done in lifting the block, and the total work input is the work done by the pulling force.
The work done in lifting the block is given by the formula: work = force x distance x cos(theta), where theta is the angle between the force and the displacement.
In this case, the force is the weight of the block, which is given by: F = m x g = 50 kg x 9.8 m/s^2 = 490 N.
The distance lifted by the block is given by: d = h / sin(theta), where h is the height the block is lifted.
Let's assume that the block is lifted to a height of 1 meter. Then, we have: d = 1 / sin(53) = 1.28 meters.
So, the work done in lifting the block is: work = 490 N x 1.28 m x cos(53) = 295 J.
The work done by the pulling force is given by: work = force x distance, where the distance is the length of the inclined plane. Let's assume that the length of the inclined plane is 2 meters. Then, we have: work = 490 N x 2 m = 980 J.
Therefore, the efficiency of the inclined plane is: efficiency = useful work output / total work input = 295 J / 980 J = 0.301 or 30.1%.