A car A is travelling on a straight level road with a uniform speed of 60 km/h. It is followed by an

English

Gujarati

Hindi

2.Motion in Straight Line

medium

A car $A$ is travelling on a straight level road with a uniform speed of $60$$km/h.$It is followed by another car $B$ which is moving with a speed of $70$ $km/h.$When the distance between them is $2.5\, km$, the car $B$ is given a deceleration of $20$$km/{h^2}.$ After how much time will $ B$ catch up with $A$...........$hr$

A$1$

B$0.5$

C$0.25$

D$1/8$

Solution

(b) Let car $B$ catches, car $A$ after $‘t’$ sec, then
$60t + 2.5 = 70t – \frac{1}{2} \times 20 \times {t^2}$
==> $10{t^2} – 10t + 2.5 = 0$==> ${t^2} – t + 0.25 = 0$
$\therefore $ $t = \frac{{1 \pm \sqrt {1 – 4 \times (0.25)} }}{2} = \frac{1}{2}hr$

Standard 11

Physics

A particle starts moving from rest in a straight line with constant acceleration. After time $t_0$, acceleration changes its sign (just opposite to the initial direction), remaining the same in magnitude. Determine the time from the beginning of motion in which the particle returns to the initial position.

hard

The displacement of a body in $8\,s$ starting from rest with an acceleration of $20\,cm / s ^2$ is $…………$

easy

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

A car moving along a straight highway with speed of $126 \;\mathrm{km} h^{-1}$ is brought to a stop within a distance of $200\; \mathrm{m}$. how long(in $seconds$) does it take for the car to stop?

medium

Two trains travelling on the same track are approaching each other with equal speeds of $40\, m/s$. The drivers of the trains begin to decelerate simultaneously when they are just $2.0\, km$ apart. Assuming the decelerations to be uniform and equal, the value of the deceleration to barely avoid collision should be………$m/{s^2}$

medium

Solution

Similar Questions

The displacement of a body in $8\,s$ starting from rest with an acceleration of $20\,cm / s ^2$ is $…………$

A car moving along a straight highway with speed of $126 \;\mathrm{km} h^{-1}$ is brought to a stop within a distance of $200\; \mathrm{m}$. how long(in $seconds$) does it take for the car to stop?

Start a Free Trial Now