# Homework (Initial velocity, gravity, and falling height)

1. ### RawTalent

2
Hey I am having a bit of trouble finding the proper equation to use when solving a problem such as this...

A physics book slides off a horizontal tabletop with a speed of 1.10 m/s. It strikes the floor at 0.350 s. Ignore air resistance. Find (a) the height of the tabletop above the floor, (b) the horizontal distance from the edge of the table to the point where the book strikes the floor, and (c) the horizontal and vertical components of the book’s velocity, and the magnitude and direction of its velocity, just before the book reaches the floor.

I used this equation with no success...
1.10(.35)+1/2(-9.8)(.1225)
= .385 + (-.60025)
= -.215 m

where do i go from here? Thanks.

2. ### rl.bhat

4,435
Hi Raw Talent, welcome to PF.
When the book leaves the table top, its velocity in the downward direction is zero and in the horizontal direction is 1.1 m/s, which remains costant.

3. ### RawTalent

2
So substituting 0 m/s for initial velocity I end up with .6 meters. I am still unsure if that's correct. Can anybody tell me if I'm using the correct equation?

Last edited: Feb 9, 2011
4. ### rl.bhat

4,435
Use h = 1/2*g*t^2 and find the answer.