Calculating Velocity: Child on Ice with Thrown Ball - Physics Help

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In this physics problem, a child sliding on ice throws a ball, and the key focus is on calculating her velocity after the throw. The conservation of momentum is crucial, as the system's total momentum before and after the throw must remain constant. The child's initial momentum is calculated using her mass and velocity, while the ball's momentum is determined by its mass and velocity after being thrown. The discussion clarifies that rotational inertia is not necessary for this scenario, emphasizing the importance of translational kinetic energy and momentum conservation. Ultimately, the child's final velocity can be derived from these principles.
ArchAngel1985
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The question I'm having trouble with is:
A child of mass 28.0 kg is sliding on ice with a velocity of 2.25 m/s in the positive x direction. She is holding a 2.4 kg ball in her hand. She throws the ball straight ahead of her with a velocity of 2.70 m/s (in the x direction). What is her velocity immediately after releasing the ball?

I think I need to get the rotational inertia for the ball to get its kinetic energy but I'm not given a radius.
 
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ArchAngel1985 said:
I think I need to get the rotational inertia for the ball to get its kinetic energy but I'm not given a radius.
You won't need rotational inertia. (No reason to think rotation is involved here.)

Instead, what physical principles might be relevant? Is anything conserved as she throws the ball?
 
I think that if the mass is not given you are expected to consider only the translational K.E.

Think about momentum!
 

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