Acar driving 22.7 m/s on flat ground drives off a 42.3 m high cliff. how much time does it take to reach the ground?

The horizontal 22.7 m/s doesn't make a bit of difference.  

The whole question is:  "How long does an object dropped from rest take to fall 44.3 meters ?"

To answer that, all you need is the "drop from rest" equation:

D = (1/2) · (acceleration) · (time)²

You didn't say so, but I'll assume this story all takes place on Earth, where the acceleration of gravity is 9.81 m/s².

42.3 m = (1/2) · (9.81 m/s²) · (time)²

time² = (42.3 m) / (4.91 m/s²)

time² = (42.3/4.91) s²

time = √(42.3/4.91)  seconds

time = 2.94 seconds

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