Question

A body of mass 4 kg is moving with a uniform velocity of 5m/s.It is acted upon by a force of 12N .What will be its velocity after 1 sec?​

Answer 1

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A body of mass 4 kg is moving with a uniform velocity of 5m/s . It is acted upon by a force of 12 N .What will be its velocity after 1 sec?

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Final velocity of body = 8 m/s

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Mass of body ( m ) = 4 kg

Force ( F ) = 12 N

Time taken ( t ) = 1 s

Initial velocity ( u ) = 5 m/s

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Final velocity of body .

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$\purple{ \boxed{ \bf a = \frac{v - u}{t} }}$

$\purple{ \boxed{ \bf F = ma}}$

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$\displaystyle \sf \longrightarrow F = ma \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow F = m \bigg( \frac{v - u}{t} \bigg) \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow F = \frac{m(v - u)}{t} \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow F = \frac{mv - mu}{t} \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow 12 = \frac{4(v) - 4(5)}{1} \: \\ \\ \displaystyle \sf \longrightarrow 12 = 4v - 20 \: \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow 4v - 20 = 12 \: \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow 4v = 12+ 20 \: \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow 4v = 32 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \displaystyle \sf \longrightarrow v = \frac{32}{4} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \ \displaystyle \sf \longrightarrow v = 8 \: m {s}^{ - 1} \: \: \: \: \: \: \: \: \: \:$

$\purple{\boxed{\begin{array}{l} \sf{Final \: velocity \: of \: body = 8 \: m {s}^{ - 1}} \end{array}}}$

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• Acceleration

Acceleration is the rate at which velocity changes with time .

• Initial Velocity

Initial velocity is the velocity of the object before the effect of acceleration .

• Final Velocity

Final velocity is the velocity of the object after the effect of acceleration .

• Force

Force is the push or pull on an object with mass that causes it to change its velocity.

$\Large{\purple{\boxed{\begin{array}{l} \textsf{Equations of motion : } \\ \\ \textsf{v = u + at} \\ \\ \displaystyle\textsf{s = ut + \sf\frac{1}{2}a {t}^{2} } \\ \\ \sf {v}^{2} - {u}^{2} = 2as \end{array}}}}$