Final answer:
The baseball's initial horizontal velocity can be found by first calculating the time it takes to fall from the desk using the vertical distance and acceleration due to gravity, and then using this time to determine the velocity from the known horizontal distance.
Step-by-step explanation:
To determine how fast the baseball was rolling when it rolled off the desk, we need to analyze the motion of the ball separately in horizontal and vertical directions. Since the motion is projectile motion and assuming no air resistance, the horizontal component of the velocity remains constant throughout the motion. The time it takes for the baseball to hit the ground can be calculated using the vertical distance and the acceleration due to gravity.
The vertical motion can be described by the equation h = (1/2)gt², where h is the height of the desk (0.7 meters), g is the acceleration due to gravity (approximately 9.8 m/s²), and t is the time in seconds it takes for the ball to hit the ground. Solving for t, we get the time the ball is in the air.
Once we know the time, we can use the horizontal distance (0.25 meters) and the time to find out the horizontal velocity v = d/t, where d is the horizontal distance and t is the time.