Calculating Momentums and Velocities for Exploding Firework Parts

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Homework Help Overview

The problem involves a firework that explodes into three parts at its maximum height, requiring calculations of momentum and velocity for each part. The scenario includes determining the landing distance of one part relative to another after the explosion.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the calculation of momentum for each part, with attempts to derive initial velocities and resultant vectors. Questions arise regarding how to split the velocity of part C without knowing its angle.

Discussion Status

Some participants have provided positive feedback on the initial calculations and suggested methods for further analysis, such as splitting the velocity into components. However, there remains uncertainty about how to proceed without the angle for part C's trajectory.

Contextual Notes

Participants are working within the constraints of the problem, which does not provide the angle for part C's motion, leading to challenges in further calculations.

myoplex11
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Homework Statement


A 9.3 kg firework is launched straight up and at its maximum height 45 m it explodes into three parts. Part A (0.5 kg) moves straight down and lands 0.29 seconds after the explosion. Part B (1 kg) moves horizontally to the right and lands 10 meters from Part A. Part C moves to the left at some angle. How far from Part A does Part C land (no direction needed)?


Homework Equations





The Attempt at a Solution


can you check my work
1. Momentum for part A:
y = (Vo)t - (1/2)(9.8m/s^2)t^2
Substitute the values for y and t which are given. Solve for Vo, the initial downward velocity. Multiply the value of Vo by 0.5 kg to get the initial momentum down of A.
momentum A = 78.2967
2. Momentum for part B:
y = (1/2)gt^2 = 45m for its downward motion.
substitute the value of g and solve for t.
Vx = 10/t = 10/3.03 = 3.3m/s
momentum B = (1kg) (Vx) = 3.3

3. Resultant of the two momentums:
Did a vector addition of the momentums of A and B. The resultant will be a vector downward to the right. Determine both, magnitude and direction.
4. Momentum of part C:
That is opposite (equilibrant) of of the vector sum of A and B.
momentum C =(momA ^2 + momB ^2) ^0.5 = 78.3662
Divide the momentum of C by its mass to get the initial velocity of C.
Voc = 10.046m/s
i am stuck at this point please help thanks
 
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Hi myoplex11! :smile:

Very good technique so far. :biggrin:

Now the trick is to split C's velocity into horizontal and vertical components :wink:

(so you find t from the vertical one, and use that to find the horizontal distance)
 
But how can i split C's velocity i don't know the angle?
 
myoplex11 said:
But how can i split C's velocity i don't know the angle?

uhhh? … mCViC = -mAViA - mBViB. :smile:
 

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