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

An object of mass $2 \, kg$ is placed at rest in a frame $S_1$ moving with velocity $10 \hat{i} + 5 \hat{j} \, m/s$ and having acceleration $5 \hat{i} + 10 \hat{j} \, m/s^2$. The object is also seen by an observer standing in a frame $S_2$ moving with velocity $5 \hat{i} + 10 \hat{j} \, m/s$. Calculate the net force acting on the object with respect to the $S_1$ frame.

$A$ cricket player catches a ball of mass $120 \,g$ moving with $25 \,m/s$ speed. If the catching process is completed in $0.1 \,s$, then the magnitude of force exerted by the ball on the hand of the player will be (in $SI$ unit):

An object with mass $500 \ g$ moves along the $x$-axis with speed $v = 4 \sqrt{x} \ m/s$. The force acting on the object is ....... $N$.

When will a body of mass $20 \ kg$ moving at $15 \ m s^{-1}$,subjected to a retarding force of $100 \ N$,come to rest (in $s$)?

$A$ constant force $\overrightarrow F = F_x\hat i + F_y\hat j$ acts on a body of mass $5\, kg$. At $t = 0\, s$, its velocity is $\overrightarrow v = (6\hat i - 2\hat j)\, m/s$ and at $t = 10\, s$, its velocity is $\overrightarrow v = 6\hat j\, m/s$. Find the force $\overrightarrow F$.