What happens when acetate is rubbed with silk?

Which of the statements about waves is true? a. in longitudinal waves, particles move perpendicular to the direction the wave is traveling.b. both transverse and longitudinal waves can travel through water c. electromagnetic waves are a type of longitudinal waves.d. in a transverse wave, particles move parallel to the direction the wave is traveling.

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

Determine the fraction of the magnitude of kinetic energy lost by a neutron (m1 = 1.01 u) when it collides head-on and elastically with a target particle at rest which is 21h (heavy hydrogen, m = 2.01 u).