Download Conservation of Energy

Conservation of Energy - Bouncing Ball
 Mark the position of this 305 g ball as it falls and bounces four times. Then paste this data
into a spreadsheet.
 Delete the horizontal position values since they are not relevant to our needs.
 Use the meter stick taped to the right door frame in the video for scaling purposes.
 Translate the origin to the lowest position marked in any frame so that the floor will be the
zero reference point for potential energy.
 Plots of position-time, velocity-time, and acceleration-time are useful. Also of interest will
be a force-time graph, where force is calculated by applying Newton’s 2nd Law to the
acceleration values (F = ma).
 The position-time plot will be “piecewise” quadratic and have one-half the value of the
acceleration due to gravity as its square term coefficient (i.e., y = 4.9x2).
 The velocity-time graph will be “piecewise” linear and have the acceleration due to gravity
as the slope of each section.
 The acceleration-time plot should be “piecewise” constant, with “spikes” at each bounce.
 You can cut and paste portions of this data into new spreadsheet columns and graph the
results to obtain equations that give the acceleration of the ball as it rises and falls.
 A gravitational potential energy-time plot can be made by direct calculation of the position
data (PE = mgh).
 Once velocity values are known, a kinetic energy-time plot is easily made (KE = 0.5mv2).
 Paste the two energy columns side by side in a new spreadsheet and manipulate the next
column so that it gives their sum (Total Mechanical Energy = Gravitational Potential Energy
+ Kinetic Energy).
 You now have data for potential energy, kinetic energy, and total energy of the falling and
bouncing ball. Plot each of these on the same graph for emphasis.
 You can now evaluate how much energy was either lost or conserved in each bounce.