That all depends on the height you are discussing. Air resistance on the way will reduce the KE of the ball going up and down so the |velocity| when it next hits the floor will be less than when it leaves. I remember a project one of my students did with bouncing pingpong balls and air resistance was measurable for trajectory heights of greater than 3 or 4m (>one room height ) and he did the test in a stair well of a building with four floors (tiled concrete floors). Iirc, he used a TV camera to look at speeds so as to offset the effect of varying coefficient of restitution.Lnewqban said:Welcome, Xlotic!
It seems to me that the ball acts like a projectile among those times, being subjected to almost the same mean aerodynamic drag in the way up and in the way down (some drag-degraded mean velocity here).
Ahem ... there is a missing link. Can you provide it?sophiecentaur said:
kuruman said:
Xlotic said:
Sorry, here it is. I realize he's not actually on our line but he's a nice looking (Neanderthal) guy so what the?kuruman said:
Thanks for the link, he looks nice. Can he play the piano?sophiecentaur said:
But that (at the speeds involved) will be largely due to hysteresis as the ball flexes, I think.rcgldr said:
But air resistance is there, else all the bounces would be much closer to the same height (differing only to energy losses to inelasticity of the bounces).cjl said:
What makes you assert that the two intervals in question are the same length? It's not like it's trivial to measure.Xlotic said:
Halc said:
No tock sound at the apex events, so not going to get the answer this way.Vanadium 50 said:
Halc said:
Yeah - but the question seems to be about comparing tock-apex and apex-tock times, which are equal for a given bounce if air resistance can be neglected.Vanadium 50 said:
Yet the tocks do not tell you when the apex events occur; certainly not mid-way between tocks, except in the limit where the velocity through the sir approaches zero.Vanadium 50 said:
The question is not about the time between apex events, but how each apex event divides the flight phase. If you do it in vacuum it will be in the middle.Vanadium 50 said:
Halc said:
Suppose that we wanted to experimentally resolve this.cjl said:
The physics behind a bouncing ping-pong ball involves the principles of gravity, elasticity, and air resistance. When the ball is dropped, it accelerates towards the ground due to gravity. As it hits the ground, it compresses and changes shape, storing potential energy. This potential energy is then converted into kinetic energy as the ball bounces back up. The elasticity of the ball allows it to retain most of its energy and continue bouncing until the energy is dissipated through air resistance.
To time a bouncing ping-pong ball, you will need a stopwatch or a timer with milliseconds. Drop the ball from a specific height and start the timer as soon as the ball leaves your hand. Stop the timer when the ball reaches the same height on its first bounce. Repeat this process multiple times and calculate the average time for more accurate results.
The timing of a bouncing ping-pong ball can be affected by several factors such as the height from which it is dropped, the surface it bounces on, the air pressure, and the temperature. These factors can impact the ball's elasticity and air resistance, which can affect the speed and height of its bounces.
The timing of a bouncing ping-pong ball can change over time due to various factors such as air resistance, temperature, and wear and tear on the ball's surface. As the ball bounces, it loses energy through air resistance and may also become less elastic over time, resulting in shorter and slower bounces.
The timing of a bouncing ping-pong ball has various real-world applications, such as in sports training and ballistics testing. In sports training, athletes can use the timing of a bouncing ball to improve their reaction time and hand-eye coordination. In ballistics testing, the timing of a bouncing ball can be used to measure the impact of different surfaces on the ball's bounce, which can be useful in designing equipment for sports like tennis and golf.