A ball is thrown off a cliff with a horizontal velocity of 12. If the cliff is 51 meters tall, how many seconds will it take the ball to reach the ground? Please help ASAP

Argon, neon, and xenon are examples of

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass