15 points. give me the method. 4.The difference of wavelength of two waves of frequencies 640Hz and 480Hz respectively in a certain medium is 1m. Find the velocity of sound in that medium.

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

The two required components for a generator

Me with this and you will be marked brainliest