SATHEE: Kinematics Question 170

Kinematics Question 170

Question: A particle is moving in a straight line and passes through a point $O$ with a velocity of 6 $m s^{- 1}$ .The particle moves with a constant retardation of 2 $m s^{- 2}$ for 4 s and there after moves with constant velocity. How long after leaving $O$ does the particle return to $o$ ?

Options:

A) 3 s

B) 8 s

C) Never

D) 4 s

Show Answer

Answer:

Correct Answer: B

Solution:

[b] Let the particle moves toward right with velocity 6 m/s. due to retardation, after time $t_{1}$ , it’s velocity becomes zero,

From $v = u - a t \Rightarrow 0 = 6 - 2 \times t_{1}$
$\Rightarrow t_{1} = 3 \sec$

But retardation works on it for 4 sec.

It means after reaching point A, direction of motion gets reversed and acceleration works on the particle for next one second.

$S_{0 A} = u t_{1} - \frac{1}{2} a t_{1}^{2} = 6 \times 3 - \frac{1}{2} (2) {(3)}^{2} = 18 - 9 = 9 m$

$S_{A B} = \frac{1}{2} \times 2 \times {(1)}^{2} = 1 m$
$∴ S_{B C} = S_{0 A} - S_{A B} = 9 - 1 = 8 m$

Now velocity of the particle at point B in return journey $v = 0 + 2 \times 1 = 2 m / s$

In returen journey form B to C particle moves with constant velocity 2 m/s to cover the distance 8 m.

Time taken = $\frac{D i t^{'} s \tan c e}{V e l o c i t y} = \frac{8}{2} = 4 s$

Total time taken by particle to return at point 0 it’s $T = t_{0 A} + t_{A B} + t_{B C} = 3 + 1 + 4 = 8$ s.

Kinematics Question 170

Question: A particle is moving in a straight line and passes through a point $O$ with a velocity of 6 $m s^{- 1}$ .The particle moves with a constant retardation of 2 $m s^{- 2}$ for 4 s and there after moves with constant velocity. How long after leaving $O$ does the particle return to $o$ ?

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Kinematics Question 170

Question: A particle is moving in a straight line and passes through a point O with a velocity of 6 ms−1 .The particle moves with a constant retardation of 2 ms−2 for 4 s and there after moves with constant velocity. How long after leaving O does the particle return to o ?

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Menu

Question: A particle is moving in a straight line and passes through a point $O$ with a velocity of 6 $m s^{- 1}$ .The particle moves with a constant retardation of 2 $m s^{- 2}$ for 4 s and there after moves with constant velocity. How long after leaving $O$ does the particle return to $o$ ?