Why is not A? (2 Viewers)

[kkk579]

@kkk579 The answer given in the paper is wrong, btw.
There is nothing fundamentally wrong with your calculation, but there is no need to include the mass of the block.
All objects fall at the same rate regardless of their mass.
You can use the standard equations for uniformly accelerated motion.

But in your solution using kinematics you got 12.5, or is that from the perspective of the cliff not ground?

 

[wizzkids]

I chose my point of reference as the top of the cliff, so distances are measured from the top of the cliff.

 

[kkk579]

bump

 

[kkk579]

bump