Explanation:
You need two, maybe three things - something that's vibrating, a medium for those vibrations to propagate in, and a listener to hear it or recording equipment to pick it up
The answer is, "B", "Ammonia".
The thermosphere is a layer of Earth's atmosphere. The thermosphere is directly above the mesosphere and below the exosphere. It extends from about 90 km (56 miles) to between 500 and 1,000 km (311 to 621 miles) above our planet.
Answer: Option (d) is the correct answer.
Explanation:
A chemical reaction in which heat energy is liberated is known as an exothermic reaction.
For example, 
In an exothermic reaction, energy of reactants is more than the energy of products.
This means that potential energy of products is less than the potential energy of reactants.
Thus, we can conclude that in the reaction
, the potential energy of the products is less than that of the reactant.
Answer:

Explanation:
From the question we are told that:
Period 
Trial 1
Spring constant 
Period 
Mass 
Trial 2
Period 
Generally the equation for Spring Constant is mathematically given by
\mu=\frac{4 \pi^2 M}{T^2}
Since

Therefore



