Water is moving with a speed of 5.18 ms-1 through a pipe with a cross- sectional area of 4.20 cm3 The water gradually descends 9.66 m as the pipe increase in area to 7.60 cm3 The speed of flow at the lower level is:
Correct answer: D. 2.86 ms-1
- A. 3.0 ms-1
- B. 3.82 ms-1
- C. 5.7 ms-1
- D. 2.86 ms-1
Explanation
The correct answer is Option D:2.86 ms-1. To find the speed at the lower level, use the continuity equation: A1V1 = A2V2 where A1 and V1 are the initial area and speed, and A2 and V2 are the area and speed at the lower level. Given A1 = 4.20 cm3, V1 = 5.18 ms-1, and A2 = 7.60 cm3, solve for V2: V1 = (A1 * V1) / A2 = (4.20 * 5.18) / 7.60 = 2.86 ms-1.
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