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 cylindrical tank is filled with water to a level of 3m. A hole is opened at a height
2. A carnot engine working between 300 K and 600 K has a work output of 800J per cycle.
3. Mass and diameter of a ring is 2 kg and 1 m respectively. The moment of inertia
4. A dip needle vibrates in a vertical plane perpendicular to magnetic meridian. The time
5. Light of wavelength 500 nm is incident on a metal with work function 2.28 eV.

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