Question

A physics book slides off a horizontal tabletop with a speed of 3.90 m/s . It strikes the floor in 0.350 s . Ignore air resistance. Find the height of the tabletop above the floor.

Answer 1

(redone)
The formula we need is d = vt + 1/2at^2.  Plugging in your numbers, we get
d = 3.9*.35 + 1/2*9.8*0.1225

D = 1.965 m