What is the mass of an object whose weight is $1\,N$ (in $,kg$)?

$A$ body of mass $2\, kg$ travels according to the law $x = at + bt^2 + ct^3$,where $a = 3\, m/s$,$b = 4\, m/s^2$,and $c = 5\, m/s^3$. The force acting on the body at $t = 2\, s$ is ......... $N$.

The time taken by a force of $2 \ N$ to produce a change of momentum of $0.4 \ kg \ m \ s^{-1}$ in a body is: (in $s$)

$A$ car of mass $100 \, kg$ is moving with a velocity of $5 \, m/s$. The force required to stop it in $\frac{1}{10} \, s$ is . . . . . . $N$.

$A$ force vector applied on a mass is represented as $\vec F = 6\hat i - 8\hat j + 10\hat k$ and accelerates the body with $1\;m/s^2$. What will be the mass of the body in $kg$?

$A$ 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: