Question

S1 and S2 are spring balances. A block A is hanging from spring balanceS1 and immersed in a liquid L which is contented a beaker B. The mass of beaker B is 1 kg and the mass of liquid L is 1.5 kg. The S1 and S2balances reads 2.5 kg and 7.5 kg respectively. What will be the reading ofS1 and S2 when the block A is pulled up out of the liquid :  

Solution

Correct option is

S1 will read 2.5 kg and S2 will read 7.5 kg

 

When a body is immersed in a liquid, its experiences an up thrust u. Which make spring balance S1 to read

Apparent weight = true weight – up thrust 

  = wA – u = 2.5 kg  

S2 reads : 

    weight of B + weight of L + reaction = up thrust of A   

       

     

        

                         

                      

 

SIMILAR QUESTIONS

Q1

Water at a pressure of  flows at 2.0 m/s through a pipe of 0.02 m2 cross-sectional area which reduces to 0.01 m2. What is the pressure in the smaller in the cross-section of the pipe?

Q2

Water is flowing through two horizontal pipes of different diameters which are connected together. In the first pipe the speed of water is 4.0 m/s and the pressure is . Calculate the speed and pressure of water in the second pipe. The diameters of the pipes are 3.0 cm and 6.0 cm respectively.

Q3

A liquid is kept in a cylindrical vessel which is being rotated about its axis. The liquid rises at the sides. If the radius of the vessel is 0.05 m and the speed of rotation is 2 rev/s, find the difference in the heights of liquid at the centre of the vessel and at its sides.

                                                                              

Q4

The pressure difference between two points along a horizontal pipe, through which water is flowing, is 1.4 cm of mercury. If, due to non-uniform cross-section, the speed of flow of water at the point of greater cross-section is 60 cm/s, calculate the speed at the other point. Density of mercury . 

Q5

Water flows into a horizontal pipe whose one end is closed with a valve and the reading of a pressure gauge attached to the pipe is . This reading of the pressure gauge falls to  when the valve is opened. Calculate the speed of water flowing into the pipe.

Q6

Air is streaming past a horizontal aeroplane wing such that its speed is 120 ms–1 at the upper surface and 90 ms–1 at the lower surface. If the density of air is 1.3 kg/m3, find the difference in pressures between the two surfaces of the wing. If the wing is 10 m long and has an average width of 2 m, then calculate the gross lift on it.      

Q7

A horizontal tube has different cross-sectional areas at points A and B. The diameter of A is 4 cm and that of B is 2 cm. Two manometer limbs are attached at A and B. When a liquid of density 0.8 g/cm3 flows through the tube, the pressure-difference between the limbs of the manometer is 8 cm. calculate the rate of flow of the liquid in the tube. (g = 980 cm/s2  

Q8

 

Find out the velocity of efflux of water from a hole in the wall of a tank made at 20 m below the free surface of water in the tank.

g = 10 m/s2.

Q9

Water tank has a hole in its wall at a distance of 10 m below the free surface of water. The diameter of the hole is 2 mm. Compute the velocity of efflux of water from the hole and the rate of flow of water. (g = 9.8 m/s2

Q10

Air is blow through a pipe AB at a rate of 15 liter per minute. The cross section area of the wide portion of the pipe AB is 2 cm2 and that of the narrow potion is 0.5 cm? the difference in the water level h is :