A ball is thrown horizontally from a height of 17.7 m and hits the ground with a speed that is 3.00 times its initial speed. What is the speed in the vertical direction just before the ball hits the ground

19.76 m/s

Explanation:

Let v be the speed just before the ball hits the ground. The v/3 is the initial speed. When the ball falls to the ground its potential energy is converted to kinetic energy: where m is the mass and h = 17.7 is the vertical distance traveled, is the initial velocity , and g = 9.81 m/s2 is the gravitational acceleration. We can divide both sides by m:

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