A 70 kg student who is late to class runs up the stairs in 4.5 seconds to reach his class. If the stairs are 4 m high, how much power did the student expend? A. 62.2
B. 78.75
C. 609.8
D.771.75

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

Astone is thrown into a pond. what happens to the amplitude of the resulting waves as they get farther from the point where the stone hit the water? explain.

Amira pulls a 3 pound wagon 4 feet. how much work has she done?