D) steel wheels reduce friction, thus requiring less force to move the load. Friction between rubber and steel would be greater than steel and steel. Friction creates heat, which represents a loss of energy (which has to come from somewhere else - likely from the kinetic energy of the train)
I believe it's DNA.
Here're some sentences to explain:
Genetic material, also known as deoxyribonucleic acid<span> (</span>DNA<span>) and </span>Ribonucleic acid<span> (</span>RNA<span>), plays a fundamental role in the composition of living organisms.</span>
Note: I believe this requires a illustration to be shown.
Answer: Wherever the persons original spot was before he/she walked 15 feet to the left.
velocity = traveled distance ÷ time of the traveled distance is seconds
velocity = 600 ÷ 60
velocity = 10 m/s
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Kinetic Energy = 1/2 × mass × ( velocity )^2
KE = 1/2 × 60 × ( 10 )^2
KE = 30 × 100
KE = 3000 j
