What is the angle between the instantaneous velocity and the friction force of an object moving on a rough surface (in $^{\circ}$)?

$A$ block of mass $10\, kg$ moving at $10\, m/s$ is released to slide on a rough surface having a coefficient of friction $0.2$. It will stop after travelling a distance of ........ $m$.

$A$ conveyor belt is moving at a constant speed of $2\, ms^{-1}$. $A$ box is gently dropped on it. The coefficient of friction between them is $\mu = 0.5$. The distance that the box will move relative to the belt before coming to rest on it,(taking $g = 10\, ms^{-2}$) is ........ $m$.

$A$ block of mass $4\,kg$ is placed on a rough horizontal plane. $A$ time-dependent force $F = kt^2$ acts on the block,where $k = 2\,N/s^2$. The coefficient of friction is $\mu = 0.8$. The force of friction between the block and the plane at $t = 2\,s$ is ....... $N$.

$A$ body of mass $m$ moves with a velocity $v$ on a surface whose friction coefficient is $\mu$. If the body covers a distance $s$ before coming to rest,what is the initial velocity $v$?

$A$ body of mass $10 \,kg$ is kept on a horizontal surface. The coefficient of kinetic friction between the body and the surface is $0.5$. $A$ horizontal force of $60 \,N$ is applied on the body. The resulting acceleration of the body is about