The spring constant is 66.7 N/m
Explanation:
First of all, we have to find the magnitude of the force acting on the spring. This is equal to the weight of the mass hanging on the spring, which is:

where:
m = 0.50 kg is the mass of the object
is the acceleration of gravity
Substituting,

Now we can use Hookes' law to find the constant of the spring:

where
F is the force applied
k is the spring constant
x is the stretching of the spring
Here we have:
F = 5 N
While the stretching is
x = 0.075 m
Therefore, ignoring the negative sign in the formula (which only tells us the direction), we find the spring constant:

#LearnwithBrainly
Answer: C. The particles that make up material A have more mass than the
particles that make up material B.
You get the net force acting on the object.
The correct answer is actually D. because rapidly is an adverb of time
I hope I've helped!