Calculate Velocity of 20g Bullet Striking 15kg Mass on Spring

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Homework Help Overview

The problem involves a 20 gram bullet striking a 15 kg mass attached to a spring, resulting in the mass compressing the spring by 12 cm. The context is centered around concepts of momentum and energy conservation in a collision scenario.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the conservation of momentum and energy, with some suggesting to work backwards from the energy stored in the spring to find the initial velocity of the bullet. There is also a query regarding whether the bullet remains embedded in the block after the collision.

Discussion Status

The discussion is ongoing, with participants questioning computations and the correctness of initial answers. Hints have been provided regarding the conservation principles, but no consensus has been reached on the correct approach or answer.

Contextual Notes

Participants are operating under the assumption that there is no friction affecting the system, and they are exploring the implications of this assumption on the calculations involved.

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Homework Statement


A 20 gram bullet strikes a 15 kg mass attached to a spring. The mass slides and compresses the spring by 12 cm. Calculate the velocity of the bullet initially. (No Friction!)

k=200n/m


bullet mass spring
=D I---------I II
I ICCCCCCCCCII
____I________I__________II

sorry after i posted it i realized how messed up the pic was
 
Last edited:
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Hint: Momentum is always conservedsecret hint: Energy is not conserved, until after the bullet is embedded in the block.
 
does my answer of 10.88995 m/s seem correct?
 
Not what I got, and it isn't simply off by an order of 10^n it just seems wrong. Check your computations, make sure you used the correct formula for Ke of a spring. and one more hint, work the problem backwards. Find the Energy at the end and work back until the point of the initial block's velocity, and then yaddi yaddi yadda.
 
does the bullet stay in the block?
 

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