Asap brainliest 20 !
kayla wants to know which substance would allow her voice to travel the fastest and why. what would you tell her?
a vacuum because there is no matter to slow down the sound wave.
solids because they are the most dense.
air because it is a gas and the particles are spread out and moving the fastest.
liquids because sound travels fast underwater.

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

What do we mean by the event horizon of a black hole?

The first law of thermodynamics is as follows: ∆u=q-w , which means in a system is equal to added, minus done by the system. the units for these variables are in .