Question

A car was moving with a uniform velocity. When its brake was applied, it stopped in 5 seconds with retardation of 1 m/s2. Calculate its initial velocity.
please solve it...

Answer 1

$\blue{\bold{\underline{\underline{Answer:}}}}$

$\green{\tt{\therefore{Initial\:velocity=5\:m/s}}}$

$\orange{\bold{\underline{\underline{Step-by-step\:explanation:}}}}$

$\green{\underline \bold{Given :}} \\ \tt: \implies Time \: taken(t) = 5 \: sec \\ \\ \tt: \implies Retardation(r )= 1 \: {ms}^{2} \\ \\ \red{\underline \bold{To \: Find :}} \\ \tt: \implies Initial \: velocity(u) =?$

• According to given question :

$\tt \circ \: Final \: velocity = 0 \: m/s \\ \\ \tt \circ \: Acceleration = - 1 \: {m/s}^{2} \\ \\ \bold{As \: we \: know \: that} \\ \tt: \implies v = u + at \\ \\ \tt: \implies 0 = u + ( - 1) \times 5 \\ \\ \tt: \implies - u = - 5 \\ \\ \green{\tt: \implies u = 5 \: m/s} \\ \\ \green{\tt \therefore Initial \: velocity \: of \: car \: is \: 5 \: m/s}\\\\ \blue{\bold{Some \: related \: formula}} \\ \orange{\tt \circ \: {v}^{2} = {u}^{2} + 2as} \\ \\ \orange{\tt \circ \: s = ut + \frac{1}{2} {at}^{2} }$

Answer 2

Aɴꜱᴡᴇʀ

☞ Initial velocity of the body = 5 m/s

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Gɪᴠᴇɴ

☆ Final Velocity (v) = 0 m/s

☆ Acceleration (a) = (-1 m/s²)

☆ Time (t) = 5 seconds

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Tᴏ ꜰɪɴᴅ

◕ The initial velocity (u) of the body

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Sᴛᴇᴘꜱ

❍ We know the laws of motion, in that we know that

$\underline{\boxed{\sf{\blue{v = u+at}}}}$

So substituting the given values,

$\sf\dashrightarrow 0 = u + (-1)(5)$

$\sf\dashrightarrow (-u) = (-5)$

So on cancelling the negative sign,

$\sf\pink{\dashrightarrow u = 5m/s}$

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$\Huge\sf Additional \: Information {}$

✭ Other to equations of motion are,

➳ s = ut+ $\sf\frac{1}{2}$ at

➳ v²-u² = 2as

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