Calculating Mass of Bucket to Descend 9.144m in 4s

[UrbanXrisis]

There is a pully with a rope though it. The rope of the left side is on the ground connected to a massless bucket. The right side has a man on a cliff about to jump on the rope. The man wants to descend 9.144m in exactly 4s. The question asks how much weight to put into the massless bucket for the man to descend 9.144m in exactly 4s. There isn't any inital velocity.

So, I need to find the acceleration of the man:
d=.5at^2
9.144m=.5(a)4^s
a=1.143m/s^2

Now I will find how much the mass of the bucket has to be:
m1a1=m2a2
m1(9.81)=(81.65kg)(9.81-1.143)
m=72.14kg

is this correct?

 

[cdhotfire]

Im taking it that the problem said the man weights 81.65kg, right?

 

[UrbanXrisis]

yes, forgot to say that

 

[cdhotfire]

Seems correct 2 me, good job.