What does it mean when the planets are in retrograde?

An automobile steering wheel is shown. what is the ideal mechanical advantage? if the ama is 8, what is the efficiency of the steering wheel?

Question part points submissions used suppose that 2 j of work is needed to stretch a spring from its natural length of 26 cm to a length of 36 cm. (a) how much work is needed to stretch the spring from 28 cm to 32 cm? (round your answer to two decimal places.)

The maximum wavelength of light required to eject an electron from zinc is 270nm. calculate the threshold frequency of zinc.