Determine the time needed for the load at b to attain a speed of 10 m/s, starting from rest.

Unfortunately, I can't give a definite answer because I only know two information: the initial velocity which is 0 because it is at rest, and the final velocity which is 10 m/s. To solve this, I should know one other information to determine time. It could be the constant acceleration. The useful equation to be used is:

a = (vf - v₀)/t

So, assuming that the object was dropped from a certain height, the acceleration is due to gravity which is equal to 9.81 m/s². Then,  

9.81 = (10 - 0)/t
t = 1.02  seconds