Collision of Spheres: Equal Acceleration?

In summary, we are discussing two separate collisions involving a stationary object and objects with equal mass, one with linear momentum and the other with angular momentum. The question is whether the stationary object will experience the same acceleration in both cases. It is important to consider the definition of angular momentum and whether the object is spinning, as well as the effects of friction and the trajectory of the objects involved. However, in the case of non-spinning billiard balls and inelastic collisions, the acceleration of the stationary object will be the same in both cases due to the principles of conservation of momentum.
  • #1
morrobay
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If 3 spheres have equal masses and the stationary object is in a collision
with a sphere with linear momentum . p= mv and linear speed 3m/sec
And in the second case the collision with the stationary object is with a sphere with angular momentum L = rxp
With angular speed 1 radian/ sec , radius = 3m.
Does the stationary object in these two collisions have the same acceleration ?
 
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  • #2


You'd want to try each case using conservation of momentum, and angular momentum.
In general, if angular, as well as linear, momentum is involved, the effects of the collision will not be the same as for linear momentum alone.
 
  • #3


Simon Bridge said:
You'd want to try each case using conservation of momentum, and angular momentum.
In general, if angular, as well as linear, momentum is involved, the effects of the collision will not be the same as for linear momentum alone.

Case #1 is an object at rest in a collision with an object with linear momentum p= mv
Case #2 is the same object at rest in a collision with an object with angular momentum L = rxp
My question is whether the object at rest in both of these separate collisions is
accelerated equally . All three objects have same mass. Case#1, object with linear speed 3m/sec
Case #2, object with angular speed 1 radian/sec. radius = 3m.
note: the underlying question is whether the stationary object is accelerated more in
the collision with object with angular momentum ?
 
  • #4


morrobay said:
Case #1 is an object at rest in a collision with an object with linear momentum p= mv
Case #2 is the same object at rest in a collision with an object with angular momentum L = rxp
How do you define your angular momentum, in respect to what point?
In case A there is also angular momentum, in respect to any point which is not on the ball's trajectory. And in case 2 there is linear momentum as well.
What is different in case 2? Is the ball spinning?
 
  • #5


It depends on friction and, in the case of nonzero friction, on the collision point.
Without friction, the rotation does not change anything.
 
  • #6


Consider 3 non-spinning billiard balls of equal masses:
#1 is moving in translational motion on the x-axis , v = 3m/sec , p=mv
#2 is at rest on x-axis at x=3m
#3 is in uniform circular motion in xy plane on a frictionless track at 3m from the origin, x0y0 L = rxp
In collision #1 there is one dimensional elastic collision at x =3m
So after collision v2 = (2m1/m1+m2)v1 , v2 for billiard ball #2
In collision # 2 the orbiting billiard ball is in collision with stationary billiard at x=3m y = 0
The linear speed of billiard ball in circular motion , v = ωr, (1 radian/sec ) (3m) = 3m/sec
So I am asking if the acceleration of the stationary billiard ball after collision in these two separate cases is equal ?
 
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  • #7


I don't see the relevance of the historic trajectory of ball #3. In the case of non-spinning billiard balls and inelastic collisions, all that ever matters are the initial/final masses/velocities. The two collisions will produce the same effect since these conditions are identical (apart from the orientation). Acceleration is not usually considered because it gets tricky to define a time interval of the interaction, and most of the time, all we need to use is conservation of momentum.

I'd also add that when you discuss angular momentum in the context of collisions, it is commonly assumed that you're referring to an axis of rotation which passes through the centre of mass of the body, ie. it's spinning. From the replies so far it seems that this is what everyone has understood of your question.
 
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1. What exactly is a "collision of spheres"?

A collision of spheres refers to the interaction between two or more spherical objects, where they come into contact and exert forces on each other. This can occur in various scenarios, such as in a game of billiards or in the movement of planets in space.

2. Why is it important to study the collision of spheres with equal acceleration?

The collision of spheres with equal acceleration is a fundamental concept in physics, as it helps us understand and predict the motion of objects in certain scenarios. By studying this type of collision, we can gain insight into concepts like momentum, energy, and conservation laws.

3. How are the velocities of the spheres determined after a collision with equal acceleration?

The velocities of the spheres after a collision with equal acceleration can be calculated using the conservation of momentum and energy principles. These equations take into account the masses and velocities of the spheres before and after the collision.

4. Can the collision of spheres with equal acceleration be perfectly elastic?

Yes, a collision of spheres with equal acceleration can be perfectly elastic, meaning that no energy is lost during the collision. In this type of collision, the spheres bounce off each other with the same speed and direction as before the collision.

5. How does the speed of the spheres affect the outcome of a collision with equal acceleration?

The speed of the spheres can greatly impact the outcome of a collision with equal acceleration. In general, a higher initial speed will result in a more dramatic collision, with greater changes in velocity and possibly deformation of the spheres. However, the final velocities will still follow the laws of conservation of momentum and energy.

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