At a dock, a crane lifts a 2009 kg container 20 m, swings it out over the deck of a freighter, and lowers the container into the hold of the freighter, which is 8 m below the level of the dock. the acceleration of gravity is 9.81 m/s 2 . neglect friction losses. how much work is done by the crane on the container? answer in units of kj

W = 157.5kJ

Explanation:

Assuming it moves the container at constant speed, the work done by the crane will be equal to the variation of the potential gratitational energy on the container:

 where h2= -8m  and  h1=0m

Wc = 157.5kJ

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.