Angle of incidence is 36° and so is the reflection. Both angles are equal.
T² caries directly as R³ .
This is Kepler's 3rd law of planetary motion .
Gravity is the attraction of every body to every other body due to the masses of each body. The larger the mass, the greater the force. It also depends on the distances: the closer the bodies, the greater the force. Gravity is directed toward the center of a body, and the distance is measured from the center.
When objects fall to the ground, gravity causes them to accelerate. Acceleration is a change in velocity, and velocity, in turn, is a measure of the speed and direction of motion. Gravity causes an object to fall toward the ground at a faster and faster velocity the longer the object falls.
Answer:
A. Sulfur _________ group 16 chalcogens
B. Sodium _________ group 1 alkali metals
C. Argon _________ group 18 noble gases
D. Silicon _________ group 14 carbon family
E. Chlorine _________ group 17 halogens
F. Phosphorus_________ group 15 pnicogens
Explanation:
It is given that,
An electron is released from rest in a weak electric field of, 
Vertical distance covered, 
We need to find the speed of the electron. Let its speed is v. Using third equation of motion as :

.............(1)
Electric force is
and force of gravity is
. As both forces are acting in downward direction. So, total force is:



Acceleration of the electron, 


Put the value of a in equation (1) as :


v = 0.010 m/s
So, the speed of the electron is 0.010 m/s. Hence, this is the required solution.