I think that mechanism is called a <em>"lens turret"</em>.
Just do energy spent divided by time to get your answer :). With this we can say a human might be able to!
Answer:
amplitude is commonly for transmitting messages with a radio carrier wave, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal. at the receiving end, the message signal is extracted from the modulated carrier by demodulation. frequency is the encoding of information in a carrier wave with instantaneous frequency. with digital data, the frequency of the carrier is shifted among a set of frequencies, using digits like 1 and 0
The difference is two laws of motion.