The efficiency of the wedge is low because of
width
friction
length
height

The efficiency of the wedge is low because of friction. The amount of work it supplies is small compared to the amount of work output. The internal resistance of the wedge is incredibly high due to its heavy weight at the other end of the blade.

unbalanced force

explanation:

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards