Question

Balls 1 and 2 are each thrown horizontally from the same height above level ground, but balls 2 has a great initial velocity after leaving the thrower's hand. If air resistance is negligible, how do the accelerations of the balls and the times it takes them to hit the ground compare?

Answer 1

The accelerations of balls thrown horizontally with different initial velocities are the same due to gravity, and thus, they hit the ground at the same time. The student's experiment would collect times to hit the ground to show that acceleration is independent of the object's velocity.

Step-by-step explanation:

When addressing the motions of balls 1 and 2 thrown horizontally from the same height with different initial velocities and negligible air resistance, we find that the acceleration of both balls is equal. This acceleration is solely due to gravity and is independent of the initial horizontal velocity of the balls. Therefore, both balls will have the same acceleration downward and will hit the ground at the same time. This illustrates the concept that in the absence of air resistance, the horizontal motion does not affect the vertical motion.

In an experiment designed to test this hypothesis, the student would collect data on the time it takes for each ball to hit the ground and verify that this time is the same for each ball regardless of their initial velocities or directions of motion. Observations from Figure 3.6 would also reaffirm that the horizontal velocity is constant and independent from vertical motion, and that the vertical position of the balls in free fall are the same at equal time intervals, regardless of their horizontal velocities.

Answer 2

Both horizontal accelerations are zero. Both vertical accelerations are equal . . . the acceleration of gravity. They fall for the same length of time. If thrown at the same time, then they hit the ground at the same time. A bullet shot from a high powered rifle and one dropped from the muzzle at the same time hit the ground at the same time.