Answer:
The period would decrease by sqrt(2)
Explanation:
The restoring force is given by,
F = -kx
According to Newton's second law of motion,
ma = -kx
ma + kx = 0
The time period is given by,
T =
Where
is the angular velocity and it is given by,
= 
Now if the spring constant is doubled then,

Thus,
=



Thus, The period would decrease by sqrt(2).
Hence, option D is correct.
HBr is the most powerful and dangerous acid .
Explanation:
A strong acid is one that instantly disunites or grants its protons in suspension. HBr is a strong acid. HBr is powerful than HCl or HF because the overlapping of a 1s-orbital and a 4p-orbital is surprisingly small, thus the binding is weak so splitting is very easy..
Answer:
D
Explanation:
In order to disprove an old theory you need to prove a new one that contradicts it using scientific research and experimentation
To solve this problem we will use the Newtonian theory about the speed of a body in space for which the speed of a body in the orbit of a planet is summarized as:

Where,
G = Gravitational Universal Constant
M = Mass of Planet
r = Radius of the planet ('h' would be the orbit from the surface)
The escape velocity is

Through this equation we can find the mass of the Planet in function of the distance, therefore



The orbital velocity is





The time period of revolution is,




Therefore the orbital period of the satellite is closes to 1 hour and 12 min