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Two identical objects with the same initial speed collide and stick together. If the composite object moves with half the initial speed of either object, what was the angle between the initial velocities?

Short Answer

Expert verified
The angle between the initial velocities is \(\theta = \cos^{-1}(1/2)\), which is approximately 60 degrees.

Step by step solution

01

Understand the conservation of momentum

The conservation of momentum implies that the total momentum before the collision is equal to the total momentum after the collision. In this case, since the objects have the same mass and speed before collision, their total momentum is \(2Mv\), where \(v\) is the initial speed and \(M\) is the mass.
02

Calculate the total momentum after collision

After the collision, the objects stick together and move with half the initial speed, therefore, their total speed is \(Mv/2\), and since they are moving together their mass is now \(2M\), hence the total momentum after collision is \(2M * (v/2) = Mv\).
03

Equate the momentum before and after collision

To find the angle of collision, equate the momentum before and after collision. This gives us the following equation: \(2Mv = 2Mv \cos(\theta)\), where \(\theta\) is the angle between the vectors of initial velocities.
04

Find the angle

Solving for \(\theta\), we get \(\theta = \cos^{-1}(1/2)\).

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