It is difficult to move a cycle with brakes on because

The coefficients of static and kinetic friction for a block on a rough surface are $0.6$ and $0.4$ respectively. The minimum force required to set the block in motion is $64 \, N$. If this force continues to be applied after the block starts moving,what will be the acceleration of the block?

$A$ block is projected with speed $20 \,m/s$ on a rough horizontal surface. The coefficient of friction $(\mu)$ between the surfaces varies with time $(t)$ as shown in the figure. The speed of the body at the end of $4 \,s$ will be ............ $m/s$ $(g = 10 \,m/s^2)$.

$A$ particle of mass '$m$' at rest on a rough horizontal surface with a coefficient of friction '$\mu$' is given a velocity '$u$'. The average power imparted by friction before it stops is:

$A$ stationary body of mass $m$ is slowly lowered onto a massive platform of mass $M$ $(M \gg m)$ moving at a speed $V_p = 4 \, m/s$ as shown in the figure. How far will the body slide along the platform (in $, m$)? (Given: $\mu = 0.2$ and $g = 10 \, m/s^2$)

$A$ wooden block of mass $m$ resting on a rough surface (coefficient of friction $\mu$) is pulled by a force $F$ at an angle $\theta$ with the horizontal,as shown in the figure. The acceleration of the block moving horizontally is: