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A particle moving along a straight line with uniform acceleration displaces by \(13 \mathrm{~m}\) and \(7 \mathrm{~m}\) in second and fifth second of its motion respectively. Column-I (A) Distance (in \(\mathrm{m}\) ) travelled in first \(9 \mathrm{~s}\) (B) Magnitude of acceleration (in \(\mathrm{ms}^{-2}\) ) of particle (C) Displacement (in \(\mathrm{m}\) ) in first \(7 \mathrm{~s}\) (D) Time (in s) when displacement is zero Column-II (1) 63 (2) 2 (3) 65 (4) 16

Short Answer

Expert verified
The matching pairs are: (A) and (1), (B) and (2), (C) and (3) and (D) and (4). Therefore, the distance travelled in first 9s is 63m, the magnitude of acceleration is 2 m/s², the displacement in first 7s is 65m and the time when displacement is zero is 16s.

Step by step solution

01

Understand the Problem

A particle moves in a straight line with uniform acceleration and displaces by 13 m in the second second and 7 m in the fifth second. It is necessary to find the distance travelled in the first 9 seconds, the magnitude of acceleration, the displacement in the first 7 seconds, and the time when the displacement is zero.
02

Calculation of Acceleration

The displacement in nth second \(s_n\) can be written as, \(s_n = u + (n - 1/2) a\), where u is the initial velocity and a is the acceleration. The displacement in the second second is 13 m, and that in the fifth second is 7 m. Solving these two equations (second second and fifth second), we get acceleration a as 2 m/s².
03

Calculation of Initial Velocity

Substitute the acceleration value obtained in previous step in the equation for the second second, we get initial velocity u as 11 m/s.
04

Distance Travelled in First 9 Seconds

Use the first equation of motion \(s = ut + 1/2 a t^2\), where s is the distance and t is time. By substituting u = 11 m/s, a = 2 m/s², and t = 9 s, we get s = 63 m.
05

Displacement in First 7 Seconds

Again, use the first equation of motion and by substituting u, a and t = 7 s, we get s = 65 m.
06

Time when Displacement is Zero

The displacement becomes zero when the particle comes to rest. Use the equation \(v = u + at\), where v is the final velocity and substituting v = 0, u = 11 m/s, a = 2 m/s², we get t = 16 s.

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