A projectile is fired upward, so its vertical velocity will Slow down, stop, speed up.
Speed up, stop, speed up.
Slow down, stop, slow down

Slow down, stop, speed up.

It slows due to gravity (acting against gravity due to upward motion), stops because at maximum height vertical velocity is zero and the body has only the horizontal velocity, speed up due to action of gravity on the body due to downward motion.

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