How Do You Calculate Final Velocity with Given Force and Time?

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Homework Help Overview

The discussion revolves around calculating the final velocity of an object given its initial velocity, mass, force, and time. The context includes concepts from kinematics and dynamics.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore different equations to find the final velocity, including the impulse-momentum theorem and kinematic equations. There is uncertainty about the relevance of impulse in the problem. Some participants question the correctness of their algebra and the application of the equations.

Discussion Status

The discussion is active, with participants sharing their calculations and questioning each other's approaches. There is no explicit consensus on the correct method, but some guidance has been offered regarding the use of acceleration derived from force and mass.

Contextual Notes

Participants note the initial velocity and average force provided, as well as the potential confusion surrounding the use of impulse in the calculations. There is an acknowledgment of the average velocity mentioned in the problem statement.

KatieLynn
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Homework Statement



Find the final velocity of the object if it is initially moving along the x-axis with average velocity of -62 m/s.

Other information
mass=.462kg
time=5s
average force = 0.8N
impulse=4

Homework Equations



F=m(Vf-Vi)/t

The Attempt at a Solution



I use the equation like this

(0.8N)=(.426kg)(Vf+62m/s)/(5s)

=-61.13m/s Is that right?
 
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I don't know why they gave you impulse, you can solve the problem with this equation:

Vf = Vi + at

where Vf=final velocity, Vi=initial velocity, a=acc. and t=time.

Remember - the acc. is .8/.462 because F=ma, so a=F/m.

Good luck!
 
Vf = Vi + atVf= (-62m.s) + (.8/.462)(5)

= -53.3 m/s

Thats what I got but it isn't right. I'm sure I didn't up the algebra, did I plug something in wrong?
 
well then i guess your initial approach is correct. the equation I gave might not work because i didnt read the part that said "avg velocity". I think your -61 is correct
 

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