<span>fast-moving particles colliding with slow-moving particles</span>
Answer:
Explanation:
Given
Initially Reading on the odometer is 
Final reading on the odometer is 
Time taken is 
average velocity 



Thus the average velocity of mail truck is 
I think everything looks good but 2 might not be right, it might be B
Answer: All of our energy comes from the sun, which is our nearest star. The sun sends out huge amounts of energy through its rays every day. We call this energy solar energy or radiant energy. Without the sun, life on earth would not exist, since our planet would be totally frozen.
Because of the rule of mask.