A body of mass \(10 \mathrm{~kg}\) has constant velocity of \(10 \mathrm{~m} \mathrm{~s}^{-1}\). A constant…
A body of mass \(10 \mathrm{~kg}\) has constant velocity of \(10 \mathrm{~m} \mathrm{~s}^{-1}\). A constant force is applied for a duration of \(4 \mathrm{~s}\) on the object and gives it a speed of \(2 \mathrm{~m} \mathrm{~s}^{-1}\) in opposite direction. Then, find acceleration produced in it.
\(3 \mathrm{~ms}^{-2}\)
\(-3 \mathrm{~ms}^{-2}\)
\(0.3 \mathrm{~ms}^{-2}\)
\(-0.3 \mathrm{~ms}^{-2}\)
Solution
Mass of body, \(m=10 \mathrm{~kg}\)
Velocity, \(v=10 \mathrm{~ms}^{-1}\)
\(t=4 \mathrm{~s}\)
Final velocity of the body,
\(v=-2 \mathrm{~ms}^{-1}\)
Since, final velocity of the body decreases on application of constant force, hence acceleration is negative.
By first equation of motion,
$\begin{aligned}
& v = u + a t \\
& \quad a = \frac{v-u}{t} = \frac{-2-10}{4} = -\frac{12}{4} = -3 \, \mathrm{ms}^{-2}
\end{aligned}$