Please help with a simple Physics question! Regions of compression and rarefaction help define .

a. electromagnetic waves
b. longitudinal waves, but not transverse waves
c. transverse waves, but not longitudinal waves
d. all mechanical waves

SERIOUS ANSWERS PLEASE, THANK YOU AND GOD BLESS

Order the sequence of ideas that lead to marie curies discovery of radioactive elements number the events in chronological order starting with the oldest

Two cannon balls weighing 18 kg and 24 kg are chained together and fired horizontally with a velocity of 165 m/s from the top of a 21-m wall. the chain breaks during the flight of the cannonballs and the 18-kg cannonball strikes the ground at t = 1.5 s, at a distance of 240 m from the foot of the wall, and 7 m to the right of the line of fire. determine the position of the other cannonball at that instant. neglect the resistance of the air.

A10-kg isto a of 10 m at aa0.9 kg/m.30 kg of ,at aas10-m .. ( 9.8 m/s2 g.)