In the early age of rocket motion it was assumed by many peope that a rocket would not work in outer space becaue there was no air for the exhaust gases to push against. Explain why the rocket does work in outer space.

Does the centre of mass of a rocket in free space accelerate? Explain. Can the speed of a rocket exceed the exhaust speed of the fuel? Explain.

Does the centre of mass of a rocket in free space accelerate? Explain. Can the speed of a rocket exceed the exhaust speed of the fuel? Explain.

A rocket can move in air free space, but a jet plane cannot. Why?

A rocket drifting sideways in outer spaces from position 'a' to position 'b' with constant velocity. At 'b' the rocket's engine starts to produce constant thrust at right angles to line 'ab'. The engine turns off again as the rocket reaches some point 'c'. Assume that rocket is subjected to no other forces.

Rama watched in discovery channel that ini outer space, at greater heights above the surface of the Earth where atmosphere does not exist appears completely dark. Explain what would be the reason for this?

Components of loudspeaker : A loudspeaker consists of permanent magnets, basket, voice cails, flexible supension & rigid speaker cone as shown in figure. Loudspeaker principle A light voice coil is mounted so that it can move freely inside the magnetic field of a strong permanent magnet. the paper cone is attached to the voice coil and attached with a flexble mounting to the outer ring of the support .Because there is a definite equilibrium position for the speaker cone and there is elasticity of the mounting structure, there is inevitably a free cone resonant frequency like of a mass on a spring. The frequency can be determined by adjusting the mass and stiffness of the cone and voice coil Working : The ratio drives a rapidly changing current through the coil. The current follows that vibrations of speech and the electromagnetic force follows the current changes, pushing the paper cone. Finally the air in front of the loudspeaker is set into vibration following the cone's motion, and sound waves are transmitted to the listener The principle of loudspeaker is :