$A$ 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?

$A$ body of mass $4 \ kg$ experiences two forces $\overrightarrow{F}_1 = 5 \hat{i} + 8 \hat{j} + 7 \hat{k}$ and $\overrightarrow{F}_2 = 3 \hat{i} - 4 \hat{j} - 3 \hat{k}$. The acceleration acting on the body is :

The average resisting force that must act on a $5 \,kg$ mass to reduce its speed from $65 \,cm/s$ to $15 \,cm/s$ in $0.2 \,s$ is .......... $N$.

$A$ body of mass $500\,g$ moves along the $x$-axis such that its velocity varies with displacement $x$ according to the relation $v = 10\sqrt{x}\,m/s$. The force acting on the body is $...........\,N$.

$A$ cricketer catches a ball of mass $150\; g$ in $0.1\; s$ moving with a speed of $20\; m/s$. The force experienced by the cricketer is ..... $N$.

When a body is acted upon by a constant force,then which of the following quantities remains constant?