(A) Let the initial acceleration be $a_1$. Since the car starts from rest,$u = 0$. After $t_1 = 9 \ s$,the velocity becomes $v = a_1 t_1 = 9a_1$. Thus

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

(A) Let the initial acceleration be $a_1$. Since the car starts from rest,$u = 0$. After $t_1 = 9 \ s$,the velocity becomes $v = a_1 t_1 = 9a_1$. Thus,$a_1 = v/9$.Next,the motorist maintains the speed $v$ for $t_2 = 50 \ s$.Finally,the motorist decelerates to rest. Let the deceleration be $a_2$. We are given $a_2 = 3a_1 = 3(v/9) = v/3$.Using the equation of motion $v_f = u_f - a_2 t_3$,where $v_f = 0$ (final rest),$u_f = v$ (initial speed for this phase),and $t_3$ is the time taken to stop:$0 = v - (v/3) t_3$$v = (v/3) t_3$$t_3 = 3 \ s$.

Class 11 Physics Motion in Straight Line Uniformly Accelerated Motion

Medium

$A$ motorist starting a car from rest accelerates uniformly to a speed of $v \ m/s$ in $9 \ s$. He maintains this speed for another $50 \ s$ and then applies the brakes and decelerates uniformly to rest. His deceleration is numerically equal to three times his previous acceleration. Then the time during which the deceleration takes place is .......... $s$ :-

A
$3$
B
$9$
C
$27$
D
$6$

Explore More

Browse All

Question Bank

All Subjects

Class 11 Questions

Class 11

Physics Questions

Chapter

Motion in Straight Line

Subtopic

Uniformly Accelerated Motion

Give examples of a one-dimensional motion where:
$(a)$ The particle moving along positive $x$-direction comes to rest periodically and moves forward.
$(b)$ The particle moving along positive $x$-direction comes to rest periodically and moves backward.

Medium

View Solution

$A$ particle of mass $1\,kg$ is moving along the $x-$axis,where its velocity depends on the $x-$coordinate as $v = 2\sqrt{x}\,m/s$. Find the net force acting on the particle $2\,s$ after the start of motion.

Medium

View Solution

The displacement $x$ (in $m$) of a particle of mass $m$ (in $kg$) moving in one dimension under the action of a force,is related to time $t$ (in $s$) by $t = \sqrt{x} + 3$. The displacement of the particle when its velocity is zero,will be

DifficultKCET 2022

View Solution

$A$ three-wheeler starts from rest,accelerates uniformly with $1\; m/s^{2}$ on a straight road for $10\; s$,and then moves with uniform velocity. Plot the distance covered by the vehicle during the $n^{\text{th}}$ second $(n = 1, 2, 3, \ldots)$ versus $n$. What do you expect this plot to be during accelerated motion: a straight line or a parabola?

Medium

View Solution

If the velocity of a particle is given by $v = (180 - 16x)^{1/2} \text{ m/s}$,then its acceleration will be ....... $\text{m/s}^2$.

Difficult

View Solution

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial

For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free

For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo

Similar Questions

Give examples of a one-dimensional motion where:$(a)$ The particle moving along positive $x$-direction comes to rest periodically and moves forward.$(b)$ The particle moving along positive $x$-direction comes to rest periodically and moves backward.

$A$ particle of mass $1\,kg$ is moving along the $x-$axis,where its velocity depends on the $x-$coordinate as $v = 2\sqrt{x}\,m/s$. Find the net force acting on the particle $2\,s$ after the start of motion.

The displacement $x$ (in $m$) of a particle of mass $m$ (in $kg$) moving in one dimension under the action of a force,is related to time $t$ (in $s$) by $t = \sqrt{x} + 3$. The displacement of the particle when its velocity is zero,will be

If the velocity of a particle is given by $v = (180 - 16x)^{1/2} \text{ m/s}$,then its acceleration will be ....... $\text{m/s}^2$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module

Give examples of a one-dimensional motion where:
$(a)$ The particle moving along positive $x$-direction comes to rest periodically and moves forward.
$(b)$ The particle moving along positive $x$-direction comes to rest periodically and moves backward.