Answer:3.49 m/s
Explanation:
Given
Speed of marble at Bottom 
Diameter of loop 
As Energy is conserved therefore Energy at top is equal to energy at bottom

,where
is the velocity at bottom







The answer to this question is a the estimate the speed of light
Earths Rotation
Earth's rotation is the rotation of Planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north<span> pole star Polaris, Earth turns counter</span>clockwise<span>. </span>
"AB84"