Answer:
harmful effects
1. that will cause air pollution
2. that will destroy our earth
Answer:
Option C. Light waves can travel through space, sound waves cannot.
Explanation:
Light is an electromagnetic wave which requires no Meduim for propagation. However, sound wave requires a medium for propagation. Since space is empty, sound can not travel through it.
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Answer:
The average speed for the whole journey is 49.5 miles per hour.
Explanation:
Step 1 :
Here, both the ways, he covers the same distance. Then, the formula to find average speed is
= 2xy / (x+y)
Step 2 :
x ----> Rate at which he travels from New York to Washington
x = 45
y ----> Rate at which he travels from New York to Washington
y = 55
Step 3 :
So, the average speed is
= (2 ⋅ 45 ⋅ 55) / (45 + 55)
= 4950 / 100
= 49.5
