Which of the following is the potential energy of a roller coaster cart with a mass of 250 kg as it sits atop the hill 20 m high before beginning the drop back downward at 5 m/s? a
25000 J
b
1250 J
c
5000 J
d
49000 J

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

Which of the following is a characteristic shared by both electron and light microscopes? a. they both employ the use of objective lenses. b. both microscopes require an internal camera to visualize the specimen. c. both microscopes have a resolving power of 0.01 nm. d. they both utilize white light to magnify the specimen.

In addition to gravity, what is the other predominant force that affects the motion of a pendulum?