Which part of a compressional wave has the lowest density?

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In which type of system is power held solely by the central government and not shared with regional governments? group of answer choices federal unitary confederate oligarchic

Ablock of mass m slides on a horizontal frictionless table with an initial speed v0 . it then compresses a spring of force constant k and is brought to rest. the acceleration of gravity is 9.8 m/s2 . how much is the spring compressed x from its natural length?