Answer:
C. Burning coal tends to harm the environment more than using solar panels.
Explanation:
When coal is burned, it reacts with the oxygen in the air. This reaction converts the stored potential energy, which turns into thermal energy, which is released as heat. But it also produces methane and carbon dioxide which is released into the air.
Answer:
0.02585 BTU
Explanation:
Given: Spring constant, k = 270 lbf/in
Initial force, f =100 lbf
Compression, x = 1 in
Work done can be calculated as follows:

Answer:
85.556metres
Explanation:
Using pythagorean theorem
C²=A²+B²
we have c as the hypotenuse vector A thus:
93.8²=A²+38.4²
93.8²-38.4²=A²
8794.44-1474.56=A²
7319.88=A²
A=85.556