Aball thrown horizontally from a point 30.0 m above the ground strikes the ground after travelling a horizontal distance of 18.0 m. with what speed was it thrown? (g = 9.8 m/s²)

The components of the ball's position at time are

The ball stops 18.0 m from where it began, so that

From the second equation, we can show that the ball travels for about seconds, which means it was initially thrown with a horizontal velocity of

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )