Initial Velocity, Equal Mass Collision: Angle Calculation

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Homework Help Overview

The discussion revolves around a completely inelastic collision between two objects of equal mass, each initially moving with speed v. After the collision, they move together with a speed of v/3, and the problem seeks to determine the angle between their initial directions.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the application of conservation of momentum and the need for a diagram to visualize the problem. There are questions about the relevance of the coefficient of elasticity in the context of a completely inelastic collision.

Discussion Status

The conversation includes attempts to clarify the problem setup and the assumptions involved. Some participants express uncertainty about the initial conditions and the implications of the collision type. There is no explicit consensus on the angle, but there are suggestions to work through the calculations.

Contextual Notes

Participants note the challenge of working with variables without specific numerical values and the potential confusion regarding the nature of inelastic collisions.

SJEllmann
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After a completely inelastic collision between two objects of equal mass, each hacing initial speed v, the two move off together with speed v/3. What was the angle between their initial directions?
 
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Where did you get stuck?
 
i don't know where to begin, i hate the problems that just give you variables.
 
Begin by drawing a diagram. Have one object move along the x-axis; the other move at some angle theta to the x-axis. Apply conservation of momentum and you'll be able to solve for theta.
 
Dang Doc! I understand that, but you want to bet the OP doesn't?

Besides, the collision is inelastic. Do we not need to know the coefficient of elasticity so we can determine how much of the energy is transferred back to the new "v" as opposed to lost in heat or other phenomena that is part of inelasticity?
 
wysard said:
Dang Doc! I understand that, but you want to bet the OP doesn't?
One step at a time. :wink:

Besides, the collision is inelastic. Do we not need to know the coefficient of elasticity so we can determine how much of the energy is transferred back to the new "v" as opposed to lost in heat or other phenomena that is part of inelasticity?
No need for such heavy artillery. The collision is completely inelastic: The two objects stick together after the collision. That's all you need to know.
 
thanks i think i got it, can someone work it out to see if they get 45 degrees as the angle?
 
SJEllmann said:
thanks i think i got it, can someone work it out to see if they get 45 degrees as the angle?
No, that's not right. Show exactly what you did.
 

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