A child pulls a sled up a snow covered hill. The child does 405 j of work on the sled. If the child walks up 15 m up the hill, how large of a force must the child exert

Phase changes are chemical changes. true or false

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

What is special about a dc circuit ?