A rock of mass 42 kg accidentally breaks loose from the edge of a cliff and falls straight down. The magnitude of the air resistance that opposes its downward motion is 255 N. What is the magnitude of the acceleration of the rock?

Question

anonymous · Answer

This is a newton's second law problem. First find the net force. Weight =mg downward. Air resistance is 255N upward. The net force is 420N-255N. Then solve for acceleration using the 2nd law. a=Net force/mass