Question

A particle of mass $0.3\, kg$ is subjected to a force $F = - kx$ with $k = 15\, N/m$. What will be its initial acceleration, if it is released from a point $20\, cm$ away from the origin ?

• A. $3\, m/s^2$
• B. $15\, m/s^2$
• C. $5\, m/s^2$
• D. $10\, m/s^2$

Answer 1

Answer: (D)

$10\, m/s^2$

Answer 2

Given : $m = 0.3\, kg, x = 20\, cm$, and $k= 15\,N/ m$ $F=-kx\,...(i)$ and $F=ma\,...(ii)$ $\therefore ma=-kx or a=-\frac{15}{0.3}\times20\times10^{-2}$ $a=-\frac{15}{3}\times2=-10\,m/s^{2}$ $\therefore$ Initial acceleration $a=10\,m/s^{2}$