Exams › JEE Main › Physics
A large cylindrical tank of base area 1 m² is filled with water and has a small hole 1 m above the bottom. A 5 kg frictionless piston sits on the water surface, and a 45 kg load is placed on the piston. When the piston (and water surface) is 7 m above the bottom, find the speed v of the water jet emerging from the hole. (g = 10 m/s²)
- 9 m/s
- 10 m/s
- 11 m/s
- 12 m/s
Correct answer: 11 m/s
Solution
Apply Bernoulli between the top surface (under the loaded piston) and the hole. The piston load supplies a constant gauge pressure, and the 6 m water column above the hole supplies the gravitational head.
Related JEE Main Physics questions
- A body is in motion inside a liquid, and the viscous resistive force on it is directly proportional to its speed. What are the dimensions of the proportionality constant?
- A capillary tube has its inner surface lined with wax and is then placed in water. Relative to a clean, unwaxed capillary, how do the contact angle (θ) and the height (h) to which water rises change?
- A charged, isolated spherical soap bubble of radius r has internal pressure equal to atmospheric pressure. If the charge on the bubble is given by Xπ√(2Tε), what is the value of X?
- Two capillary tubes, one of length L and radius R and the other of length 2L and radius 2R, are joined one after the other in series. If the flow rate through a single capillary is X = πPR⁴ / 8ηL, then the combined flow rate through the series arrangement is:
- A liquid will fail to wet the surface of a solid when the angle of contact is
- A gold sphere of a given size falls through a viscous liquid and attains a terminal speed of 0.2 m/s. If the gold has density 19.5 kg/m³ and the liquid has density 1.5 kg/m³, what terminal speed will a silver sphere of the same size have in the same liquid, given that silver has density 10.5 kg/m³?
⚔️ Practice JEE Main Physics free + battle 1v1 →