Answer:
F-F(gr) = ma
a= {F-F(gr)}/m =
=(15-10)/15=0.33 m/s² (upward)
Answer:
is the distance from the obstacle of reflection.
wavelength 
Explanation:
Given that:
- frequency of sound,

- time taken for the echo to be heard,

- speed of sound,

We know,

<em>During an echo the sound travels the same distance back and forth.</em>


is the distance from the obstacle of reflection.
<u>Now the wavelength of sound waves:</u>



Alkali metals
Nonmetals
<span>Halogens</span>
T2=r In the form of Kepler's law that can use to relate the period T and radius of the planet in our solar systems
<u>Explanation:</u>
<u>Kepler's third law:</u>
- Kepler's third law states that For all planets, the square of the orbital
period (T) of a planet is proportional to the cube of the average orbital radius (R).
- In simple words T (square) is proportional to the R(cube) T²2 ∝1 R³3
- T2 / R3 = constant = 4π ² /GM
where G = 6.67 x 10-11 N-m2 /kg2
M = mass of the foci body