A particle moves in a straight line with a constant acceleration . It changes its velocity from&nbsp

English

Gujarati

Hindi

2.Motion in Straight Line

medium

A particle moves in a straight line with a constant acceleration . It changes its velocity from $10 \,ms^{-1 }$ to $ 20\, ms^{-1 }$ while passing through a distance $135\,m$ in $t$ second. The value of $t$ is..........$s$

$12 $

$9$

$10$

$1.8$

(AIPMT-2008)

Solution

$\begin{array}{l}
{v^2} – {u^2} = 2\,as\\
Give\,v = 20\,m{s^{ – 1}},\,u = 10\,m{s^{ – 1}},\,s = 135\,m\\
\therefore a = \frac{{400 – 100}}{{2 \times 135}} = \frac{{300}}{{270}} = \frac{{10}}{9}m/{s^2}\\
\,\,\,\,\,v = u + at\, \Rightarrow \,t = \frac{{v – u}}{a} = \frac{{10m/s}}{{\frac{{10}}{9}m/{s^2}}} = 9s
\end{array}$

Standard 11

Physics

A bus moving along a straight highway with speed of $72 \mathrm{~km} / \mathrm{h}$ is brought to halt within $4 \mathrm{~s}$ after applying the brakes. The distance travelled by the bus during this time (Assume the retardation is uniform) is__________.$\mathrm{m}$.

hard

(JEE MAIN-2024)

A particle starts from rest, accelerates at $2 \,ms^{-2}$ for $10\,s$ and then goes for constant speed for $30\,s$ and then decelerates at $ 4\, ms^{-2}$ till it stops. What is the distance travelled by it………$m$

hard

(AIIMS-2002)

A train moves from rest with a uniform acceleration $a$ . Attaining a maximum speed $v$ it starts moving with uniform retardation $a$ . Assuming $s$ = total distance covered in the unidirectional motion of the train, its total time of journey and maximum speed are (respectively).

medium

An object at rest at the origin begins to move in the $+x$-direction with a uniform acceleration of $1 \,m / s ^2$ for $4 \,s$ and then it continues moving with a uniform velocity of $4 \,m / s$ in the same direction.The $x-t$ graph for object's motion will be

normal

(KVPY-2015)

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

easy

(AIIMS-1998)