Oblique impact on ground of a ping ping ball

In summary, when a ping pong ball strikes the ground obliquely without spinning, the angle of incidence is not equal to that of reflection. This is due to two main reasons. Firstly, when the ball touches the ground, it temporarily deforms and transfers its momentum to the ground before regaining its shape. This results in a reaction force that causes the ball to accelerate upwards, but due to energy loss through sound and other factors, the upward acceleration is smaller than the deceleration experienced during impact. This leads to a difference in the ball's velocity before and after impact. Secondly, the friction between the ball and the ground upon impact causes the ball to start spinning, further affecting its trajectory. This can be seen in the wheels of
  • #1
abcd8989
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When a ping pong ball strikes the ground obliquely without spinning, the angle of incidence is not equal to that of reflection, am I correct? Here is my thoughts: Assume the ground is smooth and negligible air resistance. When the ball touches the ground, it starts to deform, delivering its momentum to the ground(is it right to say so??) . After a split second, it retains its shape due to its elasticity, applying a force to the ground. A reaction force appears which causes an upward acceleration to the ball. However, due to energy loss as sound, the loss in elastic pe is less than the loss in gravitational pe before the ball reaches the ground. Therefore the upward acceleration is smaller in magnitude than the deceleration during impact. The resultant velocity of the ball after impact thus does not equal that before impact.
Please correct my mistakes, if any.
 
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  • #2
That's one reason.
And other - dominant and having reverse effect - is that ball after such collision starts spinning. Point on the bottom of the ball was moving with some horizontal speed, the same, as whole ball. After touch, in the very short time, friction stops it. In effect the ball starts to spin.

You may see the same effect much more spactacularily: watch the wheels of landing airplane at the moment of touchdown.
 
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1. How does the angle of impact affect the bounce of a ping pong ball?

The angle of impact plays a crucial role in determining the bounce of a ping pong ball. When the ball hits the ground at a shallow angle, it will have a longer contact time with the surface, resulting in a higher bounce. On the other hand, if the ball hits the ground at a steeper angle, it will have a shorter contact time and a lower bounce.

2. What factors determine the height of a ping pong ball's bounce?

The height of a ping pong ball's bounce is determined by several factors, including the angle of impact, the initial velocity of the ball, the elasticity of the ball, and air resistance. These factors interact with each other to determine the final height of the bounce.

3. How does the surface of the ground affect the bounce of a ping pong ball?

The surface of the ground can have a significant impact on the bounce of a ping pong ball. A smooth, hard surface will result in a higher bounce compared to a rough or soft surface. This is because a smooth surface allows for a more elastic collision between the ball and the ground, while a rough or soft surface absorbs more of the ball's energy.

4. Can the temperature of the ground affect the bounce of a ping pong ball?

Yes, the temperature of the ground can affect the bounce of a ping pong ball. When the ground is colder, it becomes harder and less elastic, resulting in a lower bounce. On the other hand, warmer temperatures make the ground softer and more elastic, leading to a higher bounce.

5. How does spin on a ping pong ball affect its bounce on the ground?

Spin on a ping pong ball can significantly affect its bounce on the ground. When a ball with backspin (rotating backwards) hits the ground, it will experience a lift force, causing it to bounce higher. In contrast, a ball with topspin (rotating forwards) will experience a downward force, resulting in a lower bounce. Additionally, the direction of the spin can also affect the angle of the bounce.

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