$A$ particle of mass $m$ is at rest at the origin at time $t = 0$. It is subjected to a force $F(t) = F_0e^{-bt}$ in the $x$-direction. Its speed $v(t)$ is depicted by which of the following curves?

$A$ constant force $F$ acts on two different masses $m_1$ and $m_2$ independently and produces accelerations $A_1$ and $A_2$ respectively. When the same force $F$ acts on their combined mass $(m_1 + m_2)$,the acceleration $A$ produced is:

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

$A$ force separately produces accelerations of $18 \ m/s^2$, $9 \ m/s^2$, and $6 \ m/s^2$ in three bodies of masses $P$, $Q$, and $R$ respectively. If the same force is applied on a body of mass $P+Q+R$, then the acceleration of that body is: (in $m/s^2$)

$A$ force of $100 \, dynes$ acts on a mass of $5 \, g$ for $10 \, s$. The velocity produced is ......... $cm/s$.

$A$ spherical body of mass $2\,kg$ starting from rest acquires a kinetic energy of $10000\,J$ at the end of $5^{\text{th}}$ second. The force acting on the body is $.....N$.