AIIMS2018Physics-Motion

AIIMS 2018 Physics Equations of Motion MCQ Question

Type: MCQ-numerical-Medium-Class 11

The water drops fall at regular intervals from a tap 5 m5\text{ m} above the ground. The third drop is leaving the tap at an instant when the first drop touches the ground. How far above the ground is the second drop at that instant ? (Take g=10 m/s2g = 10\text{ m/s}^2)

A

1.25 m1.25\text{ m}

B

2.50 m2.50\text{ m}

C

3.75 m3.75\text{ m}

D

5.00 m5.00\text{ m}

Correct Answer

Option C

Detailed Explanation

To find the distance covered by the second drop in 0.5 seconds, we first note that the second drop is released 0.5 seconds after the first. By the time the second drop falls for 0.5 seconds, the first drop has already fallen for 1 second, covering a distance of S1=12gt2=12(10m/s2)(12)=5mS_1 = \frac{1}{2} g t^2 = \frac{1}{2} (10 \, \text{m/s}^2)(1^2) = 5 \, \text{m}. In the next 0.5 seconds, the second drop falls S2=12g(0.5)2=12(10)(0.25)=1.25mS_2 = \frac{1}{2} g (0.5)^2 = \frac{1}{2} (10)(0.25) = 1.25 \, \text{m}, but the first drop continues to fall, covering an additional S1=12g(1.5)2=12(10)(2.25)=11.25mS_1' = \frac{1}{2} g (1.5)^2 = \frac{1}{2} (10)(2.25) = 11.25 \, \text{m}. Thus, the total distance from the starting point for the second drop after 1 second is 5+1.25=6.25m5 + 1.25 = 6.25 \, \text{m}, while the distance covered by the first drop in the same time is $ 11.25 , \text{

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