Answer:
Helium
Explanation:
Helium is the least reactive element, since it is a noble gas with the smallest amount of valence rings.
Answer:
5.7141 m
Explanation:
Here the potential and kinetic energy will balance each other

This is the initial velocity of the system and the final velocity is 0
t = Time taken = 0.04 seconds
F = Force = 18000 N
a = Acceleration
g = Acceleration due to gravity = 9.81 m/s²
Equation of motion

From Newton's second law

Squarring both sides

The height from which the student fell is 5.7141 m
Answer:
Max speed = 
Max acceleration = 
Explanation:
Given the description of period and amplitude, the SHM could be described by:

and its angular velocity can be calculated doing the derivative:

And therefore, the tangential velocity is calculated by multiplying this expression times the radius of the movement (3 m):
and is given in m/s.
Then the maximum speed is obtained when the cosine function becomes "1", and that gives:
Max speed = 
The acceleration is found from the derivative of the velocity expression, and therefore given by:

and the maximum of the function will be obtained when the sine expression becomes "-1", which will render:
Max acceleration = 