Answer:
Sometimes I fly as fast as the speed of light. Sometime I crawl as slow as a snail. Unknown until I am measured but you will certainly miss me when Iām gone.
I help engines spin and pants stay up
What word when read from left to right is a ruler, but when read from right to left is a servant?
I tell people to be careful when handling boxes.
What is always in front of you but can't be seen?
I spend most of my day eating white. When I am quick enough I get rewarded with fruit and something blue. In a dark room with blue walls I run from the ghosts that roam the halls