An automobile, travelling at 40, km/h , can be stopped at a distance of 40, m by applying brakes. If

English

Gujarati

Hindi

2.Motion in Straight Line

medium

An automobile, travelling at $40\, km/h$, can be stopped at a distance of $40\, m$ by applying brakes. If the same automobile is travelling at $80\, km/h$, the minimum stopping distance, in metres, is (assume no skidding)..........$m$

$75$

$160$

$100$

$150$

(JEE MAIN-2018)

Solution

$\begin{array}{l}
According\,to\,question,\,{u_1} = 40\,km/h,\,{v_1} = 0\\
and\,{s_1} = 40\,m\\
{\rm{using}}\,{{\rm{v}}^2} – {u^2} = 2as;\,{0^2} – {40^2} = 2a \times 40\,\,\,\,\,\,…\left( i \right)\\
Again,\,{0^2} – {80^2} = 2as\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,…\left( {ii} \right)\\
From\,eqn.\left( i \right)\,and\,\left( {ii} \right)\,\\
Stopping\,{\rm{ distance}},\,s = 160\,m\,\,
\end{array}$

Standard 11

Physics

A small block slides down on a smooth inclined plane, starting from rest at time $t=0 .$ Let $S_{n}$ be the distance travelled by the block in the interval $\mathrm{t}=\mathrm{n}-1$ to $\mathrm{t}=\mathrm{n} .$ Then, the ratio $\frac{\mathrm{S}_{\mathrm{n}}}{\mathrm{S}_{\mathrm{n}+1}}$ is

medium

(NEET-2021)

An engine of a train, moving with uniform acceleration, passes the signal-post with velocity $u$ and the last compartment with velocity $v$. The velocity with which middle point of the train passes the signal post is

medium

(JEE MAIN-2021)

$Assertion$ : A body with constant acceleration always moves along a straight line.
$Reason$ : A body with constant acceleration may not speed up.

easy

(AIIMS-1998)

A lift performs the first part of its ascent with uniform acceleration $a$ and the remaining with uniform retardation $2a$. If $t$ is the time of ascent, find the depth of the shaft.

normal

Two stones are thrown up simultaneously from the edge of a cliff $200 \;m$ high with inttial speeds of $15\; m s ^{-1}$ and $30 \;m s ^{-1} .$ Verify that the graph shown in Figure correctly represents the time variation of the relative position of the second stone with respect to the first. Neglect atr resistance and assume that the stones do not rebound after hitting the ground. Take $g=10\; m s ^{-2} .$ Give the equations for the linear and curved parts of the plot.

hard

An automobile, travelling at $40\, km/h$, can be stopped at a distance of $40\, m$ by applying brakes. If the same automobile is travelling at $80\, km/h$, the minimum stopping distance, in metres, is (assume no skidding)..........$m$

Solution

Similar Questions

A small block slides down on a smooth inclined plane, starting from rest at time $t=0 .$ Let $S_{n}$ be the distance travelled by the block in the interval $\mathrm{t}=\mathrm{n}-1$ to $\mathrm{t}=\mathrm{n} .$ Then, the ratio $\frac{\mathrm{S}_{\mathrm{n}}}{\mathrm{S}_{\mathrm{n}+1}}$ is

An engine of a train, moving with uniform acceleration, passes the signal-post with velocity $u$ and the last compartment with velocity $v$. The velocity with which middle point of the train passes the signal post is

$Assertion$ : A body with constant acceleration always moves along a straight line. $Reason$ : A body with constant acceleration may not speed up.

A lift performs the first part of its ascent with uniform acceleration $a$ and the remaining with uniform retardation $2a$. If $t$ is the time of ascent, find the depth of the shaft.

Start a Free Trial Now

$Assertion$ : A body with constant acceleration always moves along a straight line.
$Reason$ : A body with constant acceleration may not speed up.