Rolling ball, change of direction

In summary, when exerting lateral forces on a free-rolling ball on a plane with no slipping, the resulting path of the ball will depend on the interaction between friction and gyroscopic effects. If a force is applied from the South, the ball will start rolling to the North and eventually reach a constant speed. If the same force is suddenly applied from the West, the ball's path will change and it may end up rolling in a North-East direction. The apparent axis of rotation may also change from horizontal to eventually North-South, but this is conjecture and further input is needed.
  • #1
jonbarril
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Say I have a magic way to exert lateral forces on a free-rolling ball on a plane, with no slipping. Say I apply a force for a given period from the South, the ball starts rolling to the North and attains a constant speed. Then I suddenly apply the same force for the same period but from the West. What is the resulting path of the ball on the plane? What is the path of the balls apparent axis of rotation (how does it change from East-West to eventually North-South, does it remain horizontal)?

Thanks
--jon
 
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  • #2
If you apply just a force at the ball's CoM, and it starts rolling, the you must have friction. If you then apply the lateral force you will have an interaction of friction gyroscopic effects, which can get quite complex and counter intuitive:

 
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  • #3
Forces are associated to accelerations.
How do you believe the trajectory will change?
 
  • #4
It has been a long while since I took physics. I think the gyroscopic effect will work in favor of helping to turn the ball to the East. My guess is that the ball would end up rolling North-East. Not sure if the axis of rotation would stay flat. This is all complete conjecture. I'm hoping folks out there can give a more informed description of the ball's motion.
 

FAQ: Rolling ball, change of direction

What factors influence the change of direction of a rolling ball?

The change of direction of a rolling ball is influenced by several factors including the surface texture, the angle at which the ball is struck, the ball's speed, and any external forces such as wind or friction. Additionally, the ball's mass and shape can also play a role in how it changes direction.

How does friction affect the rolling ball's change of direction?

Friction between the ball and the surface it rolls on can significantly affect its change of direction. Higher friction can slow down the ball and cause it to change direction more abruptly, while lower friction allows the ball to maintain its speed and change direction more gradually.

What role does the angle of impact play in changing a rolling ball's direction?

The angle at which an external force, such as a kick or a strike, impacts the rolling ball determines the new direction it will take. A more oblique angle will result in a more significant change in direction, while a direct hit may only alter the speed or cause a minor directional shift.

Can the material of the ball affect its change of direction?

Yes, the material of the ball can affect its change of direction. Different materials have different coefficients of friction and elasticity, which can influence how the ball interacts with the surface and external forces. For instance, a rubber ball might bounce and change direction differently compared to a metal ball.

How does the initial speed of the ball influence its change of direction?

The initial speed of the ball plays a crucial role in determining how easily it can change direction. A faster-moving ball has more momentum, making it harder to change direction abruptly. Conversely, a slower-moving ball can change direction more easily when subjected to external forces.

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