The correct answer to the question is: 4) 74.9 N/m.
Step-by-step explanation:
As per the question, the stretched length of the spring is given as x = 0.250 m.
The potential energy gained by the spring is given as 2.34 joules.
We are asked to calculate the spring constant of the spring.
The potential energy gained by the spring is nothing else than the elastic potential energy .
The elastic potential energy of the spring is calculated as -
Potential energy P.E =

⇒k =

=

= 74.88 N/m
= 74.9 N/m. [ans]
Hence, the force constant of the spring is 74.9 N/m.