I think it’s B I could be wrong but I tried lol
Answer:
1) k = 10 [N/m]
2) a-) x = 0.4 [m]
b) x = 0.075 [m]
Explanation:
To be able to solve this type of problems that include springs we must use Hooke's law, which relates the force to the deformed length of the spring and in the same way to the spring coefficient.
F = k*x
where:
F = force [N] (units of Newtons]
k = spring constant [N/m]
x = distance = 10 [cm] = 0.1 [m]
Now, the weight is equal to the product of the mass by the gravity
W = m*g = F
where:
m = mass = 100 [g] = 0.1 [kg]
g = gravity acceleration = 10 [m/s²]
F = 0.1*10 = 1 [N]
Now clearing k
k = F/x
k = 1/0.1
k = 10 [N/m]
2)
a ) if the force is 4 [N]
clearing x
x = F/k
x = 4/10
x = 0.4 [m]
m = 75 [g] = 0.075 [kg]
W = m*g = F
F = 0.075*10 = 0.75 [N]
x = .75/10
x = 0.075 [m]
Answer:
(C) 16 radians
Explanation:
The angular displacement is given by the following equation:

Here
Is the angular displacement of the body at the indicated time (t).
Is the angular velocity of the body at the initial moment.
Is the angular acceleration of the body.
The disk starts from rest, so 
Replacing the given values:

The correct option is: (A) <span>The energy before is equal to the energy afterward.
Explanation:
According to the law of conservation of Energy, energy can neither be created nor destroyed; it can only be transformed into one form or another. It means that the total initial energy must be equal to the total final energy of the system. By considering this law, we can infer that the energy before is equal to the energy afterward.</span>