Problem 12-28: Engineering Mechanics- Dynamics (Hibbeler 14th Edition)

Two Projectiles Passing Each Other: Constant Acceleration

This lesson applies the constant-acceleration position equation to two balls launched simultaneously in opposite directions along a vertical line. By setting the two position functions equal, students discover that the shared gravitational term cancels, reducing the problem to a simple linear equation for the meeting time and height.

Question:
Ball A is thrown vertically upward from the top of a 30-meter-high building with an initial velocity of 5 meters per second. At the same instant, ball B is thrown vertically upward from the ground with an initial velocity of 20 meters per second. Determine the height above the ground and the time at which the two balls pass each other.

In this lesson, you will learn to:
• Derive position equations for objects under constant gravitational acceleration using integration of kinematics equati