**Q:** A tennis ball is thrown vertically upward with an initial velocity of +6.7 m/s. What will the ballâ€™s velocity be when it returns to its starting point? The acceleration of gravity is 9.81 m/s^2.

**A:**

Its velocity will be – 6.7 m/s.

This is true for anything that is thrown vertically upwards. Look at a parabola’s shape to figure out why. It’s symmetrical!

The kinematics equation for height actually represents a parabola’s equation:

Compare this to a similar form for a parabola:

It’s true what they say: what goes up, must go down.

At any point, it will come down with the same magnitude of velocity it had on its way up, with the sign reversed to indicate that the direction is opposite.

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