A body initially at rest is moving with uniform acceleration a m/s²

⇦

⇨

A body initially at rest is moving with uniform acceleration a m/s².It’s velocity after n second is v.The displacement of the body in last 2s is

Options

(a) 2v(n-1)/n
(b) v(n-1)/n
(c) v(n+1)/n
(d) 2v(2n+1)/n

Correct Answer:

2v(n-1)/n

Explanation:

v = u + a t —-(1)
Let the velocity of the particle be v’ just two seconds before which means t=(n-2) seconds
Since initial velocity=0.
on applying eqn(1),
v’=0+a(n-2)
Now, S = u t + (1/2) a t²
So the displacement in the last two seconds is
Here the velocity before two seconds as found above is {(n-2)a}
which becomes initial velocity for last 2s and time is 2s because we want displacement for last 2s
S = {a (n-2) } 2 + (1/2) a (2²)
S = 2 a (n-2) + 2a
S= 2an-2a
S= 2a(n-1)
Acceleration is a=v/n
Displacement for last 2s = 2v(n-1)/n .

Related Questions:

1. A bus is moving with a speed of 10 ms⁻¹ on a straight road
2. α-particles, deuterons and protons of same energy are moving in a perpendicular
3. A charge of 100 μC has a potential at a distance of 9 m is
4. In a series resonant LCR circuit, the voltage across R is 100 volts and R =1kΩ
5. Time taken by light to cross a glass slab of thickness 4 mm and refractive index 3 is

Topics: Motion in Straight Line (93)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends