Rolling Objects With Slipping Question

In summary, we have a ball with a nonuniform radially symmetric mass distribution that is projected across a floor with an initial velocity v. To start rolling without slipping, v must equal rw, which means that rw must increase. The force of friction is not mentioned, but can be taken into account by considering the equations for acceleration and angular acceleration. Alternatively, the angular momentum about a point on the floor is not affected by friction, so it can also be used to determine the final velocity. The total energy of the ball can be calculated using rotational-kinematics formulas.
  • #1
Axxaaa
3
0
Consider a ball of radius r and total mass m, with a nonuniform but radially symmetric mass distribution inside it, so that it can have an almost arbitrary moment of inertia I. (a) If this ball is projected across a floor with an initial velocity v, and is at first purely sliding across the floor, what is its final velocity when it is rolling without slipping. (b) What is the total energy of the ball?

Equations:
T = I * α
v = r * w
a = r *α
rotational-kinematics formulas

I do not know how to even begin. For the ball to start rolling without slipping, v must equal rw, which means rw must increase. There is no mention of force of friction that might provide the angular acceleration in this problem, so I am quite lost.
 
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  • #2
Hi Axxaaa! Welcome to PF! :smile:
Axxaaa said:
There is no mention of force of friction that might provide the angular acceleration in this problem, so I am quite lost.

Call the kinetic friction "F", and write out the equations for a and α

you should find that F cancels out in the end. :wink:

Show us what you get. :smile:
 
  • #3
Another approach is to consider the angular momentum about a point on the floor. Since friction acts along the floor it will not affect that.
 

Related to Rolling Objects With Slipping Question

1. What is the difference between rolling and sliding when it comes to moving objects?

Rolling refers to the motion of an object where it rotates about an axis while also moving in a linear direction, such as a ball rolling down a hill. Sliding, on the other hand, is the motion of an object moving in a linear direction without any rotation, such as a box being pushed across a table.

2. How does slipping affect the motion of a rolling object?

Slipping occurs when there is not enough friction between the rolling object and the surface it is rolling on. This can cause the object to lose control and change its direction, or even stop rolling altogether. It can also cause the object to roll at a different speed than expected.

3. What factors can influence the amount of slipping in a rolling object?

The amount of slipping in a rolling object can be influenced by several factors, including the surface material and texture, the weight and shape of the object, and the force applied to the object. Other factors such as temperature and air resistance can also play a role.

4. How does friction play a role in the motion of a rolling object?

Friction is the force that opposes motion between two surfaces in contact. In the case of a rolling object, friction helps to provide the necessary grip between the object and the surface to prevent slipping. However, too much friction can also slow down the rolling object.

5. Can slipping be beneficial in certain situations when rolling objects?

Yes, in some cases, slipping can be beneficial when rolling objects. For example, in sports such as bowling or curling, controlled slipping can help the object to change direction or curve towards its target. In other cases, slipping can also be used to reduce friction and increase speed, such as in the design of some roller coasters.

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