A motorist starting a car from rest accelerat | vedclass

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

Question

(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

Vedclass · Accepted Answer

$3$

Vedclass · Answer

(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$.

Similar Questions

The velocity of a bullet is reduced from $200\; m/s$ to $100\; m/s$ while travelling through a wooden block of thickness $10\; cm$. The retardation,assuming it to be uniform,will be ........... $\times 10^4\; m/s^2$.

Velocity of a body moving along a straight line with uniform acceleration $a$ reduces by $\frac{3}{4}$ of its initial velocity in time $t_0$. The total time of motion of the body till its velocity becomes zero is

The distance covered by a body of mass $5\,g$ having linear momentum $0.3\,kg\,m/s$ in $5\,s$ is $..........\,m$.

An electron starting from rest has a velocity that increases linearly with time,given by $v = kt$,where $k = 2 \, m/s^2$. The distance travelled in the first $3 \, s$ will be ........... $m$.

The distance travelled by a particle starting from rest and moving with an acceleration $\frac{4}{3} \ m/s^2$ in the third second is:

Vedclass Test Series

Exam Paper Generator

Online Exam Module