A certain model of the motion of a light plastic ball tossed into the air is given
Question:
A certain model of the motion of a light plastic ball tossed into the air is given by
\[m x^{\prime \prime}+c x^{\prime}+m g=0, \quad x(0)=0, \quad x^{\prime}(0)=v_{0}\]
Here \(m\) is the mass of the ball, \(g=9.8 \mathrm{~m} / \mathrm{s}^{2}\) is the acceleration due to gravity, and \(c\) is a measure of the damping. Because there is no \(x\) term, we can write this as a first order equation for the velocity \(v(t)=x^{\prime}(t)\) :
\[m v^{\prime}+c v+m g=0\]
a. Find the general solution for the velocity \(v(t)\) of the linear firstorder differential equation above.
b. Use the solution of part a to find the general solution for the position \(x(t)\).
c. Find an expression to determine how long it takes for the ball to reach its maximum height?
d. Assume that \(c / m=5 \mathrm{~s}^{-1}\). For \(v_{0}=5,10,15,20 \mathrm{~m} / \mathrm{s}\), plot the solution, \(x(t)\), versus the time.
e. From your plots and the expression in part \(\mathrm{c}\), determine the rise time. Do these answers agree?
f. What can you say about the time it takes for the ball to fall as compared to the rise time?
Step by Step Answer:
A Course In Mathematical Methods For Physicists
ISBN: 9781138442085
1st Edition
Authors: Russell L Herman