Answer:
73 db
Explanation:
A single air conditioner is equivalent to 70 dB frequency. An extra air conditioning unit would therefore double the sound frequency. It does not, however, double the decibels to 140 dB. Instead, it adds only 3 dB to the 70 dB, making the total decibels of two air conditioning units equal to 73 db
Hence the correct option is b that is 73 db
Answer:
c. 
Explanation:
= Initial distance between asteroid and rock = 7514 km = 7514000 m
= Final distance between asteroid and rock = 2823 km = 2823000 m
= Initial speed of rock = 136 ms⁻¹
= Final speed of rock = 392 ms⁻¹
= mass of the rock
= mass of the asteroid
Using conservation of energy
Initial Kinetic energy of rock + Initial gravitational potential energy = Final Kinetic energy of rock + Final gravitational potential energy

Answer:
<h2>velocity = 12.73 km/hr.</h2><h2 />
Explanation:
velocity = distance / time
=<u> 28 km </u>
2.2 hr
= 12.73 km/hr.
The correct answer is C. Mercury and Mars have the same gravitational force
Explanation:
This chart compares the different features of two planets in our solar system (Mercury and Mars). In this chart, the only numerical value or feature that is the same for both planets is gravity because for both planets gravity is 1.7 m/s2. This implies the gravitational force or the force that attracts objects towards the center of the planet is the same or that objects are pulled with the same force in both planets. Moreover, this factor depends on others such as mass, density, among others.
Unfortunately, the given statements are missing from the problem. However, we can still determine the relationship between the electric force between two objects and the distance between them. The formula for the electric force is given below:
F = (k*Q1*Q2)/d^2
k is a constant, while Q1 and Q2 are the respective charges of the objects. F is force, while d is distance.
As seen in the formula, we can see that the electric force F is inversely proportional to the square of the distance between the two objects.