What is the velocity of a quarter dropped from a tower after 10 seconds?

U = 0, the initial vertical velocity

Assume g = 9.8 m/s² and ignore air resistance.

Use the formula
v = u + gt
where v =  vertical velocity after t seconds.
That is,
v = 0 + (9.8 m/s²)*(10 s) = 98.0 m/s

98.0 m/s

26.4 is about the right time