ATAR Notes: Forum
HSC Stuff => HSC Science Stuff => HSC Subjects + Help => HSC Physics => Topic started by: Jefferson on September 15, 2019, 11:47:36 pm
-
A 10 kg rock is dropped from rest and falls vertically for 5.0 seconds. After this time, the rock was moving at 40.0 m/s. What was the work done against air friction in this time?
(A) 12 kJ
(B) 4 kJ
(C) 9 kJ
(D) 100 J
Answer is (B) 4 kJ.
Could someone help me with this?
I'm getting 1.8 kJ instead.