Explanation:
It is given that,
length of steel wire, l = 0.75 m
Mass of the wire, m = 12 g = 0.012 kg
Fundamental frequency, f = 120 Hz
We need to find the mass of the anvil (m'). The fundamental frequency is given by :

v is the speed of the mass
Speed is given by :

is the mass per unit length,

T is the tension in the wire,



T = 518.4 N
Tension in the wire, T = m' g


m' = 52.89 kg
So, the mass of the anvil is 52.89 kg. Hence, this is the required solution.
But we do not know whether the force is pushing or pulling (the same direction (both forces are parallel) but: .........[ ]<-F-- or .......[ ]--F-->). I suppose the correct answer is B
Answer: D(t) = 
Explanation: A harmonic motion of a spring can be modeled by a sinusoidal function, which, in general, is of the form:
y =
or y = 
where:
|a| is initil displacement
is period
For a Damped Harmonic Motion, i.e., when the spring doesn't bounce up and down forever, equations for displacement is:
or 
For this question in particular, initial displacement is maximum at 8cm, so it is used the cosine function:
period =
12 =
ω = 
Replacing values:

The equation of displacement, D(t), of a spring with damping factor is
.
Complete Question:
Suppose that an asteroid traveling straight toward the center of the earth were to collide with our planet at the equator and bury itself just below the surface. What would have to be the mass of this asteroid, in terms of the earth’s mass M, for the day to become 25.0% longer than it presently is as a result of the collision? Assume that the asteroid is very small compared to the earth and that the earth is uniform throughout.
Answer:
m = 0.001 M
For the whole process check the following page: https://www.slader.com/discussion/question/suppose-that-an-asteroid-traveling-straight-toward-the-center-of-the-earth-were-to-collide-with-our/