Question

Jack drops a tennis ball from the top of a skyscraper allowing it to fall freely. Neglecting air resistance, what is the velocity of the tennis ball at the end of 5 seconds?

A.)9.81m/s^2
B.)49.0m/s^2
C.)29.4m/s^2
D.)88.7m/s^2

Answer 1

To determine the velocity of the ball falling, we need to use one kinematic equation which will allow as to calculate for the height of the skyscraper. This formula is expressed as:

y = v0t + at^2 / 2

v0 = 0 since it started at rest
a = g since it acts upon the gravitational force
t = 5 s

y = (9.81)(5)^2 / 2
y = 122.625 m

To obtain velocity we divide the height with time,

v = 122.625 / 5 = 24.53 m/s

closest would be option C.