A grindstone has moment of inertia `0.5kgm^2`.What constant torque should be applied so that it attains an angular velocity of `120`rpm in `8sec`.
In the above case what is the rate at which work is done at the end of `8sec`.

The reaction A rarr X is a first order reaction which takes place in a vessel with initial concentration of A as 10 M. The rate constant for this reaction is 4.16 h^(-1) . In the presence of a catalyst, the reaction A rarr Y follows second-order kinetics and the rate constant is 0.2 min^(-1) M^(-1) . What should be the initial concentration of A in the presence of catalyst so that the value of t_(1//2) for both the reactions is the same?

A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two verical wires at its ends. A current of 5.0 A is set up in the rod through the wires. a. What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero? b. What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before? (Ignore the mass of the wires.) g = 9.8 m/s^(2) .

A 100 turn closely wound circular cell of radius 10 cm carries a current of 3.2A (a) what is the field at the centre of the coil? (b) What is the magnetic moment of this coil? The coil is placed in a vertical plane and is free to rotate about a horizontal axis which coincides with its diameter. A uniform magnetic field 2 T in the horizontal direction exists such that initially the axis of the coil is in the direction of the field. The coil rotates through an angle of 90^(o) under the influence of the magnetic field (c) What are the magnitudes of the torques on the coil in the initial and final position? (d) What is the angular speed acquired by the coil when it has rotated by 90^(o) ? The moment of inertia of the coil is 0.1 kg m^(2) .