The velocity of the bullet becomes one third after it penetrates $4\,cm$ in a wooden block. Assuming that bullet is facing a constant resistance during its motion in the block. The bullet stops completely after travelling at $(4+x)\,cm$ inside the block. The value of $x$ is$.....$

Acceleration versus time graph of a body starting from rest is shown in the figure. The velocity versus time graph of the body is given by

The displacement of a particle after time $t$ is given by $x = \left( {k/{b^2}} \right)\left( {1 - {e^{ - bt}}} \right)$ where $b$ is a constant. What is the acceleration of the particle? 

A body moves on a frictionless plane starting from rest. If $\mathrm{S}_{\mathrm{n}}$ is distance moved between $\mathrm{t}=\mathrm{n}-1$ and $\mathrm{t}$ $=\mathrm{n}$ and $\mathrm{S}_{\mathrm{n}-1}$ is distance moved between $\mathrm{t}=\mathrm{n}-2$ and $t=n-1$, then the ratio $\frac{S_{n-1}}{S_n}$ is $\left(1-\frac{2}{x}\right)$ for $n$ $=10$. The value of $x$ is

A particle moves along a straight line. Its position at any instant is given by $x=32 t-\frac{8 t^3}{4}$, where $x$ is in metre and $t$ is in second. Find the acceleration of the particle at the instant when particle is at rest $..........\,m / s ^2$

The velocity $u$ and displacement $r$ of a body are related as $u^2 = kr$, where $k$ is a constant. What will be the velocity after $1\, second$ ? (Given that the displacement is zero at $t = 0$)