What is wrong with following physics equations? (velocity and acceleration)

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SUMMARY

The discussion centers on the correct application of kinematic equations in physics, specifically addressing the relationships between average velocity, initial velocity, final velocity, and acceleration. The participant initially misapplies the formula Vf = at, which is only valid when the initial velocity (Vi) is zero. The correct formulation should be Vf = Vi + at, which incorporates the initial velocity. The confusion arises from the incorrect manipulation of the equations leading to an erroneous expression for height (h).

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Selfphysicslearner
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vavg=(Vi+Vf)/2
vavg=h/t
then vavg*t=h
h=(Vi+Vf)/2 * t
Vf=at
(Vit+at2)*1/2=h
But formula on every resource I found says it should be;
(Vit+at2*1/2)=h
What mistake did I do ?
 

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Selfphysicslearner said:
Vf=at
Is it?
Are you missing anything here?
 
Last edited by a moderator:
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Selfphysicslearner said:
Vf=at
This is not generally correct.
 
cnh1995 said:
Is it?
Are you missing anything here?
I see it must be actually:Vf=Vi+at then there is 2 Vi in formula which eliminates 1/2 multiplied makes it
h=1/at^2 +2*1/2Vi
 
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What are the fundamental units of acceleration?
 
Selfphysicslearner said:
vavg=(Vi+Vf)/2
vavg=h/t
then vavg*t=h
h=(Vi+Vf)/2 * t
Vf=at
(Vit+at2)*1/2=h
But formula on every resource I found says it should be;
(Vit+at2*1/2)=h
What mistake did I do ?
Vf=at , this equation means final velocity = acceleration * time. This can happen only if initial velocity is 0, but in the equation Vi is the initial velocity and Vi is not 0 as per the equations wrriten.
 

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