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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 .
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Topics: Motion in Straight Line
(93)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- Given a sample of radium-226 having half-life of 4 days. Find the probability,
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- The lowest frequency of light that will cause the emission of photoelectrons
- If the alternating current I=I₁ cosωt+I₂ sinωt, then the rms current is given by
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Topics: Motion in Straight Line (93)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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