Collision With Linear and Angular Momentum

AI Thread Summary
The discussion focuses on calculating the average force during a collision involving a rolling complex object, specifically a sphere with an additional mass on its edge. The initial conditions include a velocity of 20 m/s and a stopping distance of 0.01 m. The user is attempting to apply impulse to find the average force but is uncertain about incorporating the rotational aspect of the system. There is confusion regarding the inertia of the two masses and whether they are treated as concentric. The importance of rotational inertia in the calculations is emphasized, indicating it significantly impacts the overall dynamics of the collision.
drakoniis
Messages
2
Reaction score
0

Homework Statement



Find the average force of the collision of a rolling complex object (assume sphere for inner object: 0.2m with another object along the edge with its density concentrated into a point: 1.2m from center, 10kg, and the total radius to contact surfaces is 1.2m) if the object is originally rolling without slipping, traveling at a velocity of 20 m/s, and is brought to a stop within 0.01m.


Homework Equations



v_0 = 20 m/s, \ \ \ v_f = 0 m/s
m_1 = 40 kg, \ \ \ r_1 = 0.2 m
m_2 = 10 kg, \ \ \ r_2 = 1.2 m
x_0 = 0 m, \ \ \ x_f = 0.01 m


The Attempt at a Solution



I'm trying using impulse, but I'm not sure how to include the rotational portion.

<br /> \begin{multline*}<br /> &amp; \overline{J} = \overline{F} \Delta t = M \Delta v \\<br /> &amp; \Delta t = \frac {\Delta x} {\overline{v}} = 1 * 10^{-2} s \\<br /> &amp; \overline F = \frac { M \Delta v } { \Delta t } = \frac {50 kg * 20 m/s} {1 * 10^{-2 }s} = 1 * 10^{-6} N<br /> \end{multline*}<br />

I also know the inertia, but I'm not sure how (and if) this factors into this equation.
 
Physics news on Phys.org
I am not able to understand the system of the two spheres.Are they concentric?
 
It's treated as a single sphere, but the fact there is another mass on the edge affects the inertia calculation.
 
I'll give you a hint the rotational inertia does matter.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top