How do I determine the maximum distance, that the ball moves upward, and the time for

[R Morrison]

Homework Statement

I want to learn how to solve problems with air resistance.
The equation is shown at the website below.
http://en.wikipedia.org/wiki/Drag_(physics )


Example:
A 0.5 kg ball is thrown upward at 25 m/s. The density of the air = 1.3 kg/m^3. The drag coefficient = 0.8. Cross sectional area = 0.05 m^2

Fd = ½ * 1.3 * v^2 * 0.8 * 0.05
Fd = 0.026 * v^2
How do I determine the maximum distance, that the ball moves upward, and the time for the upward trip?

Homework Equations

Fd = ½ * density * velocity^2 * drag coefficient * Cross sectional area

The Attempt at a Solution

Fd = ½ * density * velocity^2 * drag coefficient * Cross sectional area
Fd = ½ * 1.3 * v^2 * 0.8 * 0.05
Fd = 0.026 * v^2

Net force = m * g – Force of air resistance
Net force = (0.5 * 9.8) – 0.026 * v^2
Net acceleration = Net force ÷ mass
Net acceleration = 9.8 – 0.052 * v^2

How do I determine the maximum distance, that the ball moves upward, and the time for the upward trip

 

[R Morrison]

What does edit tags meam?

 

[sckeen1988]

First, mg is acting against the initial motion of the ball, so it should be negative. From that it may be a good place to start to solve for the initial net acceleration of the ball. Then remember that a=dv/dt