In a science lab, a teacher instructed students to attach a piece of very fine steel wool to a clamp stand inside a fume hood. The students then lit a burner placed under the steel wool. The metal strands began to glow bright red and flames filled the steel wool. After the burner was turned off, the metal continued to burn, leaving behind reddish-brown strands that collapsed into a powder when it was touched after cooling. Based on these observations, did the steel wool undergo a chemical change or a physical change? Explain your answer.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

answer: a. same unit

explanation:

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr