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Khan Academy
Khan Academy: 2 D Projectile Motion: Total Final Velocity for Projectile
Explains how to calculate the total final velocity for a projectile landing at a different altitude. (There is a mistake near the end where Sal wrote 29.03 m/s when it should be 26.03 m/s, and the final total magnitude should be 26.55...
Khan Academy
Khan Academy: Correction to Total Final Velocity for Projectile
On two-dimensional projectile motion. A followup correction to the "Total Final Velocity for Projectile" video.