What was the work done against air friction?
A 10kg rock is dropped from rest and falls vertically for 5.0s. After this time the rock was moving at 49m/s. What was the work done against air friction in this time?
Sorry it was meant to be moving at 40m/s
- billrussell42Lv 71 month ago
weight is 98 N
downward force is 98 N – force of air friction (call it f)
downward acceleration is F/m = (98 – f)/10 = 9.8 – f/10
acc = ΔV/Δt = 49/5 = 9.8 m/s = 9.8 – f/10
f (force of friction) = 0
work against air resistance = 0