A student holds a water balloon outside of an open window and lets go. The window is 10 meters above the ground, and the balloon is falling under the acceleration of gravity, which is 9.8 m/s2. There are two equations that can be used to describe its motion over time:

Question

A student holds a water balloon outside of an open window and lets go. The window is 10 meters above the ground, and the balloon is falling under the acceleration of gravity, which is 9.8 m/s2. There are two equations that can be used to describe its motion over time:

x=x0+v0t+12at2

v=v0+at

Would the balloon hit the ground before or after 1.0 s of falling? Which equation did you use to decide, and what comparison did you make to determine that it would or would not hit the ground by then?

Use 3–5 sentences to explain your reasoning. And write like a fifth grader.

Answer 1

The balloon will hit the ground before 1.0 second of falling. I used the equation x=x0+v0t+12at2 to decide. In this equation, x is the position of the balloon, x0 is the initial position (which is 10 meters in this case), v0 is the initial velocity (0 because the balloon is held still), t is the time, and a is the acceleration due to gravity (which is 9.8 m/s2). So I plugged in the values and found out that the balloon would hit the ground in less than 1.0 second.