JEE MAIN - Physics (2024 - 4th April Morning Shift - No. 9)
Explanation
The distance covered by a body in the $$n^{\text{th}}$$ second can be found using the equation:
$$S_{n} = u + \dfrac{1}{2}a(2n-1)$$
where,
- $$S_{n}$$ is the distance covered in the $$n^{\text{th}}$$ second,
- $$u$$ is the initial velocity,
- $$a$$ is the acceleration, and
- $$n$$ is the nth second.
The distance covered in the $$n^{\text{th}}$$ second is given as $$102.5 \, \text{m}$$, so we have:
$$102.5 = u + \dfrac{1}{2}a(2n-1)$$ ---- (1)
For the $$(n + 2)^{\text{th}}$$ second, the distance covered is:
$$S_{n+2} = u + \dfrac{1}{2}a(2(n+2)-1)$$
Substituting $$n + 2$$ in place of $$n$$, we get:
$$115.0 = u + \dfrac{1}{2}a(2n+3)$$ ---- (2)
Subtracting equation (1) from equation (2), we get:
$$115.0 - 102.5 = \dfrac{1}{2}a(2n + 3 - 2n + 1)$$
$$12.5 = \dfrac{1}{2}a(4)$$
So, solving for $$a$$ gives:
$$a = \dfrac{12.5 \times 2}{4} = \dfrac{25}{4} = 6.25 \, \text{m/s}^2$$
Therefore, the acceleration of the body is:
$$6.25 \, \text{m/s}^2$$
Which corresponds to Option A: $$6.25 \, \text{m/s}^2$$.
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