Answer: 20kg
Explanation: the above question is base on workdone...
Note: work done is also equal to potential energy.
➡Mathematical expression for the above statement:
W = P.E. where w and p.e are noted to be work done and potential energy...
Therefore; P.E = mgh
Where m is the mass of the object, g is the acceleration due to gravity and finally h is the height...
Therefore; P.E = mgh
600 = m x 10 x 3
600 = 30m
Divide both side by the coefficient of m
Therefore; 600/30 = m
m = 20kg