22. A ball rolls off a table and falls 0.75 m to the floor, landing with a speed of 4.0 m/s. (a) What is the acceleration of the ball just before it strikes the ground? (b) What was the initial speed of the ball? (c) What initial speed must the ball have if it is to land with a speed of 5.0 m/s? 23. An astronaut on another planet tosses a rock horizontally with a speed of 6.95 m/s. The rock falls through a vertical distance of 1.40 m and lands a horizontal distance of 8.75 m from the astronaut. What is the acceleration of gravity on the planet? 24. A ball is thrown horizontally from the top of a cliff with a velocity of 10. m/s. The height of the cliff above the ground is 45 m. Calculate (a) the time to reach the ground, (b) the distance from the cliff of the ball on hitting the ground, and (c) the velocity (the magnitude and the angle) with which it hits the ground