I cannot see all the questions, what is 18,19 and 21? (:
"Free fall" means that gravity is the ONLY force acting on the object. If there's air resistance, then it isn't free-fall.
Objects that fall near earths surface are ALWAYS falling through air, unless they're inside some kind of a vacuum chamber with all the air removed from it.
Answer:
elementary particles
Explanation:
Matter is composed of elementary particles i.e. quarks and leptons.
Matter is composed of elementary particles which is called quarks and leptons. Quarks consist of protons, neutrons and electrons. All observable matter is made up of up quarks, down quarks and electrons.
Lepton is an elementary particle consist of half-integer spin that does not undergo strong interactions. Leptons exist on two main classes i.e. charged leptons, and neutral leptons. Electron, electron neutrino, muon, muon neutrino, tau and tau neutrino are the six types of leptons.
Answer:
True
Explanation: Tsunami is a huge displacement of water caused by Earthquakes which took place on inside the sea floor causing extreme flooding and damages to life and tsunami is more prominent in the Pacific Ocean and Indonesia mainly because of the presence of active earthquake zones beneath the ocean. Tsunami has also been observed in the Mediterranean Sea and also in the United States around the year 1933.
