Not sure what you mean but I think you are either talking about a lunch box or a thermos
Potential energy + kinetic energy = constant at every moment in time
At the highest point:
potential energy is at its maximum
kinetic energy is zero
Divide 56 by 60 then x the answer by 6 then you get 5.6km which is your answer.
Answer:
a) 0.147 N
b) 9.408 N
c) 9.261 N
Explanation:
The tension on the cord is the only force keeping the block in circular motion, thus representing the entirety of its centripetal force 
. Plugging in values for initial and final states and we get answers for a and b. The work done by the person causes the centripetal force to increase, and thus is the difference between the final tension and the initial tension.
