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स्थिर बल $\overrightarrow{ F }= F _{x} \hat{i}+ F _{y} \hat{j}$ के कारण द्रव्यमान $5 \;kg$ की एक वस्तु $t =0\; s$ पर वेग $\vec{v}=(6 \hat{i}-2 \hat{j})\; m / s$ से गतिशील है और $t =10 \;s$ पर वेग $\vec{i}=+6 \hat{j} \;m / s$ से गतिशील है। बल $\overrightarrow{ F }$ है
$\left( { - 3\hat i + 4\hat j\,} \right)\,N$
$\left( { - \frac{3}{5}\hat i + \frac{4}{5}\hat j\,} \right)\,N$
$\left( {3\hat i - 4\hat j\,} \right)\,N$
$\left( {\frac{3}{5}\hat i - \frac{4}{5}\hat j\,} \right)\,N$
Solution
$\begin{array}{l}
From\,question,\\
Mass\,of\,body,\,m = 5\,kg\\
Vleocity\,at\,t = 0,\\
u = \,\left( {6\hat i – 2\hat j} \right)\,m/s\\
Velocity\,at\,t = 10s,\\
v = + 6\,\hat j\,m/s\\
Force,\,F = ?
\end{array}$
$\begin{array}{l}
Acceleration,\,a = \frac{{v – u}}{t}\\
= \frac{{6\hat j – \left( {6\hat i – 2\hat j} \right)}}{{10}} = – 3\hat i + 4\hat j\,m/{s^2}\\
Force,\,F = ma\\
= 5 \times \frac{{\left( {3\hat i + 4\hat j} \right)}}{5} = \left( { – 3\hat i + 4\hat j} \right)\,N
\end{array}$
