In Figure 2.18, what is the total time the coin is in the air before returning to its release point?
Reasoning
During the time the coin travels upward, gravity causes its speed to decrease to zero. On the way down, however, gravity causes the coin to regain the lost speed. Thus, the time for the coin to go up is equal to the time for it to come down. In other words, the total travel time is twice the time for the upward motion. The data for the coin during the upward trip are the same as in Example 12. With these data, we can use Equation 2.4 (v
=v0+at) to find the upward travel time.
Solution Rearranging Equation 2.4 , we find that
 | |
.
It is possible to determine the total time by another method. When the coin is tossed upward and returns to its release point, the displacement for the entire trip is y=0 m. With this value for the displacement, Equation 2.8 
can be used to find the time for the entire trip directly.
