Question

A ball rolls off the edge of a balcony at 8.0 m/s. Find its speed after 3.8 s in the air. Use g = 10. m/s2

Answer 1

Vi=0, t=3.8s, a=g=10m/s^2, and Vf=?. Use Vf=Vi +at, which turns into Vf= (10m/s^2)(3.8s). Initial velocity in the y-direction is 0.

Answer 2

v(x0) =v(x)=8 m/s
v(y0) =0
v(y)=gt=10•3.8=38 m/s
v=sqrt{v(x)² +v(y)²} =
=sqrt (8²+38²) = 38.8 m/s

Answer 3

An autographed baseball rolls off of a 1.1 m
high desk and strikes the floor 0.15 m away
from the desk.
How fast was it rolling on the desk before
it fell off? The acceleration of gravity is
9.81 m/s
2
.
Answer in units of m/s