Acceleration & Force: Lesser Force Impact on Mass

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Discussion Overview

The discussion revolves around the effects of applying different forces on a body of mass m that is initially at rest and then in uniform motion. Participants explore how applying a force f2, which is less than a previously applied force f1, affects the acceleration of the body, considering various scenarios and the implications of Newton's laws of motion.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes a scenario where a body accelerates to a velocity v1 under force f1 and then moves uniformly after the force is removed.
  • Another participant states that if force f2 is applied in the opposite direction of the body's motion, it would cause retardation or deceleration.
  • It is noted that the effect of applying force f2, which is less than f1, depends on the direction of f2.
  • Some participants assert that applying force f2 less than f1 results in a new acceleration that is less than the previous acceleration (a2 < a1).
  • There is a reiteration of Newton's law (F = ma) and its implications, emphasizing that the mass does not affect the law's applicability regardless of the body's motion.
  • One participant introduces the velocity equation for constant acceleration to illustrate how the body’s velocity changes when force f2 is applied.

Areas of Agreement / Disagreement

Participants express differing views on the effects of applying force f2, particularly regarding its direction and its impact on acceleration. There is no consensus on the outcomes of applying f2 less than f1, as the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference Newton's laws and the relationship between force, mass, and acceleration, but there are unresolved assumptions regarding the direction of forces and the implications for motion.

pranav p v
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Consider a body of mass m at rest,then if I apply force f1 on that then it accelerates and attains a velocity of v1.then I remove that force..now the body is in uniform motion.if I apply a force f2 which is less than f1, then body will be accelerated or retardated?I know if same f1 is applied then acceleration will be the previous same value,and if I apply force greater than f1 then it will be accelerated ( but not uniform)..what about f2 less than f1
 
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pranav p v said:
Consider a body of mass m at rest,then if I apply force f1 on that then it accelerates and attains a velocity of v1.then I remove that force..now the body is in uniform motion.if I apply a force f2 which is less than f1, then body will be accelerated or retardated?I know if same f1 is applied then acceleration will be the previous same value,and if I apply force greater than f1 then it will be accelerated ( but not uniform)..what about f2 less than f1
Well, if you applied f2 in a direction opposite that of the body's motion, then yes it would be retarded/decelerated.
 
if I apply a force f2 which is less than f1, then body will be accelerated or retardated?

That depends on the direction of F2.

I know if same f1 is applied then acceleration will be the previous same value

Yes. If you apply F1 again the acceleration will be the same a2 = a1.

if I apply force greater than f1 then it will be accelerated ( but not uniform).

If you apply a force F2 > F1 the object will accelerate faster so a2 > a1. However if the new force is constant the new acceleration will also be constant (=uniform).

what about f2 less than f1

If F2 < F1 the new acceleration will be less than before, a2 < a1

All you need to remember is Newton's Law...
F = ma
so
a = F/m

The fact that the mass is moving does not change law.
 
F=ma, period. It doesn't remember previous action and doesn't know anything about speed.
 
Even more importantly ##\vec{F}=m \vec{a}##, i.e., force and acceleration are both vectors!
 
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pranav p v said:
Consider a body of mass m at rest,then if I apply force f1 on that then it accelerates and attains a velocity of v1.then I remove that force..now the body is in uniform motion.if I apply a force f2 which is less than f1, then body will be accelerated or retardated?I know if same f1 is applied then acceleration will be the previous same value,and if I apply force greater than f1 then it will be accelerated ( but not uniform)..what about f2 less than f1
Start with the velocity equation in case of constant acceleration:

v
(t) = v(t = t0) + a⋅(t - t0)

The body of mass m is moving with v1 when you, at time t2, suddenly apply a force f2 to the body. The acceleration is then a = f2/m. You get

v(t) = v(t = t2) + f2/m⋅(t - t2) = v1 + f2/m⋅(t - t2)
 

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