where are the answer choises
D. all of the above
Hope this helps!
<h2>
Answer: 13.61 N/m</h2>
Hooke's law establishes that the elongation of a spring is directly proportional to the modulus of the force 
applied to it, <u>as long as the spring is not permanently deformed</u>:
(1)
Where:
is the elastic constant of the spring. The higher its value, the more work it will cost to stretch the spring.
is the length of the spring without applying force.
is the length of the spring with the force applied.
According to this, we have a spring where only the force due gravity is applied.
In other words, the force applied is the weigth 
of the block:
(2)
Where 
is the mass of the block and 
is the gravity acceleration.
(3)
(4)
Knowing the force applied and 
and 
, we can substitute the values in equation (1) and find :
(5)
(6)
<u>Finally:</u>
Answer:
The answer to your question is letter B.
Explanation:
To answer this question, we must remember the third law of motion of Newton that states that For every action, there is an equal and opposite reaction.
Then, if the action force is 40 N to the right, the reaction force must be 40 N to the left.
