Movement of a Body on horizontal surface

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SUMMARY

The discussion revolves around calculating the total time of movement for a body on a horizontal surface subjected to a horizontal force equal to 60% of its weight. The body travels a distance of 24 meters, and participants analyze the forces involved, including tractive and frictional forces. The consensus indicates that the total time of movement is 6 seconds, as per the textbook answer, despite initial calculations suggesting values between 1.7 and 2.8 seconds. The problem emphasizes the need for clarity regarding friction, which is not specified in the original statement.

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  • Understanding of Newton's Second Law of Motion
  • Familiarity with kinematic equations
  • Knowledge of force components, including tractive and frictional forces
  • Basic algebra for solving equations
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  • Learn how to apply kinematic equations to solve for time and velocity
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Students studying physics, particularly those focusing on mechanics, as well as educators seeking to clarify concepts related to motion on horizontal surfaces.

inv4lid
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Homework Statement


A body that is on a horizontal surface begins to move under the action of horizontal force equal to 60% of its weight. Force acts for a while, then stops acting. Determine the total time of movement if the body has traveled a distance of 24m.

Homework Equations


gd1krNzHSbuPIJChPyJTWg.png
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I'm not really sure about the "horizontal force". Is it the tractive force or is it the resultant of the difference between the tractive and friction one?
I tried like both(but i really assume the horizontal is the resultant force) and from there we can probably get the acceleration.

The Attempt at a Solution


R = Ft - Ff = ma;
60% = 0,6;
where g is 10N/kg
0,6 m*g = ma;
6m = ma;
a = 6 (m/s2);

I've tried using that formula:
v12 - v02 = 2as
v1 - v0 = √(2as)
We don't know though any of speeds.
s = (v0 + v1)t/2
from there:
48 = (v0 + v1)t
S = v0t + a/2 * t2
24 = v0t + 3t2
tried more things but all attempts led to nothing.

Any help would be appreciated, thanks!
 

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What was the velocity of the body before it “begins to move?”

Check your algebra on solving for the final velocity.
 
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Chestermiller said:
What was the velocity of the body before it “begins to move?”

Check your algebra on solving for the final velocity.
It was 0, yes, i know.
I got some answers between 1,7 and 2,8 seconds. By the way, the end of the book says the true answer is 6s
The problem also belongs to the category of "simple problems", so I think the solution shouldn't be so
difficult. Usually, the problems of this category are solved in 1-2 steps.
 
inv4lid said:
A body that is on a horizontal surface begins to move under the action of horizontal force equal to 60% of its weight. Force acts for a while, then stops acting. Determine the total time of movement if the body has traveled a distance of 24m.
The wording strongly suggests that the "total movement" is made up of a period of constant acceleration while the force is applied, plus a further period of constant velocity. An answer of 6 seconds would then be feasible, but if this is correct then there is insufficient information to deduce it.
Please check you have provided all the information in the question.
 
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Friction isn't mentioned in the problem statement.
 

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