Can one calculate velocity from force used?

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Homework Help Overview

The discussion revolves around calculating the velocity of a 2kg object pushed with a force of 20N on a frictionless surface. Participants explore whether velocity can be determined directly from force or if work and energy concepts are necessary for the calculation.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Some participants attempt to derive acceleration from the force applied, questioning its relevance in a frictionless scenario. Others suggest that understanding the relationship between acceleration and velocity is crucial. There are inquiries about the necessary information to calculate velocity, including the role of initial conditions.

Discussion Status

The discussion is active, with participants providing insights into the relationship between force, mass, acceleration, and velocity. Some guidance has been offered regarding the integration of acceleration to find velocity, but no consensus has been reached on the necessity of work and energy concepts.

Contextual Notes

Participants note the absence of initial velocity in the problem setup and discuss the implications of this missing information on the calculations. There are also references to Newton's Laws of Motion and assumptions that may affect the analysis.

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Homework Statement


This is a general problem, but if a 2kg object is given a push with a force of 20N, would one be able to calculate the velocity of the object if the surface is frictionless? Or does one need work and energy to find out the velocity?

Homework Equations


F=ma
Work=F delta distance
KE=1/2mv2

The Attempt at a Solution


I tried to find acceleration through that but wouldn't that be irrelevant on a frictionless track?
 
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You posted equations showing that velocity can be determined from work done and mass, and that work done can be determined from force and distance force advanced.
You have quoted a mass and a force. What's missing if you want to determine the velocity?
 
Q7heng said:

Homework Statement


This is a general problem, but if a 2kg object is given a push with a force of 20N, would one be able to calculate the velocity of the object if the surface is frictionless? Or does one need work and energy to find out the velocity?

Homework Equations


F=ma
Work=F delta distance
KE=1/2mv2

The Attempt at a Solution


I tried to find acceleration through that but wouldn't that be irrelevant on a frictionless track?
Why would acceleration of the mass be irrelevant? The mass is starting out at zero velocity, so how does the velocity change?

Do you know the relationship between acceleration and velocity?

Do you know Newton's Laws of Motion?
 
Q7heng said:
This is a general problem, but if a 2kg object is given a push with a force of 20N, would one be able to calculate the velocity of the object if the surface is frictionless?

If you know the starting velocity you can work out the final velocity as a function of time...

Definition of acceleration...

dv/dt = a

Integrate both sides.

v = at + constant

The constant is the starting velocity and gives you the equation of motion...

v = at + u ....... (1)

F = ma
a = F/m .....(2)

put (2) into (1)

v = Ft/m + u

I've omitted some assumptions.
 

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