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MHT CET · Physics · Motion In One Dimension

A body of mass \(5 \mathrm{~kg}\) is moving in a straight line. The relation between its displacement and time is \(\mathrm{x}=\left(\mathrm{t}^{3}-2 \mathrm{t}-10\right) \mathrm{m}\). What is the force acting on it at the end of 5 second?

  1. A \(150 \mathrm{~N}\)
  2. B \(120 \mathrm{~N}\)
  3. C \(80 \mathrm{~N}\)
  4. D \(100 \mathrm{~N}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(150 \mathrm{~N}\)

Step-by-step Solution

Detailed explanation

A body of mass rig,
\(\begin{array}{l}
m=5 k g \\
x=\left(t^{3}-2 t-10\right) m
\end{array}\)
F after \(t=5 \mathrm{sec}\),
\(\begin{array}{l}
\frac{d x}{d t}=v=3 t^{2}-2 \\
\frac{d v}{d t}=a=6 t \\
F=m a=5 \times 6 t=30 \times 5 \\
F=150 \mathrm{~N}
\end{array}\)