Final answer:
The average velocity of the Chelyabinsk blast wave cannot be calculated without additional information on the horizontal distance covered or the exact speed of the wave. Blast waves from such events typically exceed the speed of sound, which is about 343 m/s at sea level. Without knowing the blast wave's speed, we cannot calculate its time to reach the ground at 90° or the distance it traveled in 2 minutes.
Step-by-step explanation:
On February 15, 2013, the Chelyabinsk meteor entered Earth's atmosphere and caused a significant blast wave upon exploding. To answer the student's questions regarding the average velocity and its comparison with the speed of sound, we need to perform a series of calculations.
(a) To find the average velocity of the blast wave, we can use the formula velocity = distance / time. Given that the blast wave traveled at an angle of 10° above the horizon, we would need to know the horizontal distance it covered to calculate its average velocity. However, since the distance is not provided, we cannot calculate an average velocity. We might reasonably assume a horizontal propagation and then apply trigonometry if horizontal distance and the angle are known.
(b) Without the specific velocity of the blast wave, we cannot compare it directly to the speed of sound. However, we know that blast waves from such events typically travel faster than sound in air, which is approximately 343 m/s at sea level.
(c) If the blast wave were traveling at 90° above the horizon (straight down), the time taken to reach the ground could be found by dividing the altitude the blast occurred at (23.5 km) by the speed. Since we do not know the speed of the blast wave in this problem, we cannot calculate the time.
(d) Again, without the speed of the blast wave, we cannot calculate the distance covered by the blast wave in 2 minutes.