Question 6
The graph shows positive and negative work done ( positive force and negative force is like driving a car stepping on accelerator or brakes)
Net WD = change in KE
+1+ (-3) = KE f - KE i
-2 = KEf - 2
KEf = 0
v = 0 (the block come to a rest after 5.0 m )
Question 7
a) WD = change in KE = 36J
b) WD = Fs
F = 36/0.010 = 3600 N
Assuming force applied is perpendicular to weight
Question 8
Use the formula : Force = -(gradient of PE-x graph)
Force = positive (repulsive/away)for negative gradient
Force = negative (attractive/towards)for positive gradient
Hence ans C
