How does the law of conservation of energy apply to machinesBased on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work?

According,to the law of conservation of energy,the amount of energy in a closed system always stay constant. ... So,the amount of work output and other transformed energy is equal to the amount of energy inputs. • In this way,the conservation of energy is fulfilled by the machines.

the diagram which shows forces as either balanced = same speed or unbalanced = accelerarting

it is the second option.