During a lab activity in class, you are trying to collect data on a marble to determine its launch (initial) velocity. You decide to launch the marble at 90 degrees (vertically
straight up) and measure the maximum height of the marble. After several trials of
data, you determine the average maximum height to be 4.2 m above the initial height
of the marble. Based on your measurements, what is the launch (initial) velocity of the
marble?
Assume acceleration due to gravity is -9.81 m/s2. Answer in units of meters/second.