A long, uniform slinky is stretched straight on a smooth floor. At different times the slinky is (i) pushed and pulled along its length and (ii) shaken up and down to generate waves.
(a) Define a longitudinal wave and a transverse wave.
(b) For case (i) above, draw a labelled sketch showing the direction of particle vibration and the direction of wave propagation, marking one compression (C) and one rarefaction (R).
(c) State any two differences between longitudinal and transverse waves on the basis of (i) particle vibration and (ii) presence of compressions/rarefactions or crests/troughs.
(d) Sound is heard on the Earth but not on the Moon. Explain clearly why sound, though produced by vibrating objects, cannot travel through the interplanetary vacuum while light from the Sun can.