Based on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work? move the machine to a different gravitational field. increase the friction between its moving parts. reduce the friction between its moving parts. redefine the machine’s system boundaries.

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by