An electric fan, with effective area of cross-section 'A', accelerates air of density 'rho' to a speed 'v'. What is the power needed for this process ?

What is the effect on resistance, if the area of cross section is increased.

A plank of area of cross-section A is half immersed in liquid 1 of density rho and half in liquid 2 of density 2rho . What is period of osciallation of the plank if it is slightly depressed downwards?

A plank of area of cross-section A is half immersed in liquid 1 of density rho and half in liquid 2 of density 2rho . What is period of osciallation of the plank if it is slightly depressed downwards?

Statement- 1 : When an electric fan is switched on in a closed room, the air of the room is cooled. Statement- 2 : When fan is switched on, the speed of the air molecules will increase.

Statement- 1 : When an electric fan is switched on in a closed room, the air of the room is cooled. Statement- 2 : When fan is switched on, the speed of the air molecules will increase.

Statement- 1 : When an electric fan is switched on in a closed room, the air of the room is cooled. Statement- 2 : When fan is switched on, the speed of the air molecules will increase.

If a solid cylinder of area of cross-section A is moving with velocity V in medium of density p then power loss of cylinder is

If a solid cylinder of area of cross-section A is moving with velocity V in medium of density p then power loss of cylinder is