Question

given a,s,u in a problem,decide which equation of motion to use to find v?​

Answer 1

$\huge\bf\red {Answer}$

If we have given,

Acceleration (a)

Displacement (s)

Initial Velocity (u)

Then we can find Final velocity(v) by the given equation-

$\huge\bf\boxed {{ {v}^{2} - {u}^{2} = 2as}}$

Because there is (a)Acceleration , (s) displacement and (u) initial velocity are given, the value of final velocity(v) can be find easily by this equation.

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We didn't use here other 2 equations of motion beacause,

In the first equation of motion-

v = u + at

According to question (a) Acceleration, (s) displacement and (u) intial velocity must be given in the equation to find the value of (v) final velocity.

But (s)displacement is not given in the equation and we also need time(t) to solve the equation but it is also not given, so we can't find the value of (v) final velocity using this equation if (a), (s) and (u) are given.

In the second equation of motion-

s = ut + 1/2 at^2

In this equation there is no (v) final velocity comes, so by this equation we can't find the value of (v) final velocity.

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Note - First see what physical quantities are given in the question then you can solve it easily.

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Answer 2

Answer:-

Given:-

• Value of (s).
• Value of (u).
• Value of (a).

To Find:-

Value of (v).

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Equations of Motion:-

1. v = u + at
2. s = ut + ½at²
3. 2as = v² - u²

So, we'll use the 3rd one to fetch the value of the final Velocity.

since,

2as = v² - u²

➵ v² - u² = 2as

➵ v² = 2as + u²

➵ v = √2as + u² [Whole root]