Answer:4A
Explanation:
Given
Mass is displace x= A units from its mean position x=0'
When it is set to free it will oscillate about its mean position with maximum amplitude A i.e. from x=-A to x=A
One cycle is completed when block returns to its original position
so first block will go equilibrium position x=0 and then to x=-A
from x=-A it again moves back to x=0 and finally back to its starting position x=A
so it travels a distance of A+A+A+A=4A
Explanation:
Atoms are the components of ordinary matter, also called baryonic matter, which only represents 4% of the universe, while the remaining 96% would be formed by what is known as dark matter and dark energy which constitute two of the unsolved problems in physics.
Answer:

Explanation:
Let the charge on the ball bearing is q.
charge on glass bead, Q = 20 nC = 20 x 10^-9 C
Force between them, F = 0.018 N
Distance between them, d = 1 cm = 0.01 m
By use of Coulomb's law in electrostatics

By substituting the values


Thus, the charge on the ball bearing is 
Refraction is a phenomenon which results when a ray of light enters from one medium to another medium. When a ray of light enters from denser medium to rarer medium, it bends away from the normal. The laws of refraction are: The incident ray, the refracted ray and the normal all lie in the same plane.