A 60kg rock in on a mountain in banff national park breaks free from a ledge and falls down 500 meters to the bottom of the mountain the average air resistance is 150N what is the average acceleration of the rock?

Using Newton's law that F = ma.

The force here is the net force. The forces acting in opposite direction are the weight and the air resistance. The weight of course is acting downwards and the air resistance is pushing upwards.

Therefore:

W - AR = ma W = Weight = mg, AR = Air Resistance = 150.

g = 10 m/s2

mg - AR = ma

60 (10) - 150 = 60a

600 - 150 = 60a

450 = 60a

60a = 450

a = 450/60

a = 7.5 m/s2

Cheers.