If an automobile engine develops a power of `7.5xx10^4` W when rotating at 1800 rpm, what torque does it deliver?

A small body is kept at a distance of 7 cm from the centre of a gramophone disc. The disc starts rotating with gradually increasing speed and the body is just on the verge of being thrown off when the disc rotates at 60 rpm. What will be the rate of rotation of the disc when the body, kept at a distance of 12 cm from the centre, is just being thrown off?

In a capillary tube water rises up to a certain height and the upward force due to surface tension balances the force of 7.5xx10^-4 N due to weight of water. If the surface tension of water is 6xx10^-2 N. m^-1 then what will be the internal circumference of the capillary tube?

What will be the approximate terminal velocity of a rain drop of diameter 1.8xx10^-3 m , when density of rain water ~~10^3 kg. m^-3 and the coefficient of viscosity of air ~~1.8xx10^-5 N.s. m^-2 ?(Neglect buoyancy of air)

The mechanical equivalent of heat is 4.2 xx 10^(7) erg cdot cal^(-1) . What does it mean?

A reaction , Xrarr products , is first order. If takes 40min for its concentration to drop from 0.1 (M) to 5xx10^(-3)(M) .What would the concentration of X be , when the rate of the reaction is 7.5xx10^(-4)(M)"min"^(-1) -

If the mean free-path of gaseous molecule is 60 cm.at a pressure of 1xx10^(-4) mm mercury, what will be its mean free-path when the pressure is increased to 1xx10^(-2) mm mercury

What will be th approximate terminal velocity of a rain drop of diameter 1.8xx10^(-3)m . When density of rain water ~~10^(3) kgm^(-3) and the co-efficient of viscosity of air ~~1.8xx10^(-5) Nsm^(-2) ? (Neglect buoyacy of air)

A steam engine delivers 5.4 xx 10^(8)J of work per minute and services 3.6 xx 10^(9) J of heat per minute from its boiler. What is the efficiency of the engine? How much heat is wasted per minute?