11.

A rod of weight w is supported by two parallel knife edges A and B and is in equilibrium in a horizontal position. The knives are at distance d from each other. The centre of mass of the rod is at distance x from A. The normal reaction on A is

• 
• 
• 
• 

A mass m moves in a circle on a smooth horizontal plane with velocity v_o at a radius R_o. The mass is attached to a string which passes through a smooth hole in the plane as shown.

The tension in the string is increased gradually and finally m moves in a circle in a circle of radius R_o/2. The final values of the kinetic energy is

• mv₀²

• 1/4mv_o²

• 2mv_o²

• 2mv_o²

Three identical spherical shells, each of mass m and radius r are placed as shown in the figure. Consider an axis XX^', which is touching to two shells and passing through the diameter of the third shell. Moment of inertia of the system consisting of these three spherical shells about XX' axis is

• 11/5 mr²

• 3 mr²

• 16/5 mr²

• 16/5 mr²

Two spherical bodies of masses M and 5M and radii R and 2R are released in free space with initial separation between their centres equal to 12 R. If they attract each other due to gravitational force only, then the distance covered by the smaller body before collision is

• 2.5 R

• 4.5 R

• 7.5 R 

• 1.5 R 

The approximate depth of an ocean is 2700 m.The compressibility of water is 45.4 x 10^-11 Pa^-1 and density of water is 10³ kg/m³. What obtained at  the bottom of the ocean?

• 0.8 x10^-2

• 1.0 x 10^-2

• 1.2 x 10^-2

• 1.2 x 10^-2

The two ends of a metal rod are maintained at temperatures 100^o C and 110^o C. The rate of heat flow in the rod is found to be 4.0 J/s. If the ends are maintained at temperatures 200^o C and 210^o C, the rate of heat flow will be

• 44.0 J/s

• 16.8 J/s

• 8.0 J/s

• 8.0 J/s

The wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250m². Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be( p_air = 1.2 kg/m³)

• 4.8 x 10⁵ N, downwards

• 4.8 x10⁵ N , upwards

• 2.4 x 10⁵ N , upwards

• 2.4 x 10⁵ N , upwards

A Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work is done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature is

• 100J 

• 99 J 

• 90 J

• 90 J

The ratio of the specific heats  in terms of degrees of freedom (n) is given by

When two displacements represented by  are superimposed, the motion is 

• not a simple harmonic

• simple harmonic with amplitude a/b

• simple harmonic with amplitude 

• simple harmonic with amplitude