a mass of 0.5 kg is attached to a spring. the mass is then displace from its equilibrium position by 5cm and released. its speed as it passes the equilibrium position is 50cm/s.

and what is your question?

the max energy in the spring at 5cm is equal to the KE as it passes equilibirum
max energy=1/2 m v^2=1/2 (.5)(.50^2)
so k for the spring must be
PE=1/2 k x^2
k=2(1/2*.5)(.50^2)/(.05^2) in Joules/meter

To solve this problem, we can use the concepts of simple harmonic motion and energy conservation.

First, let's find the spring constant (k) of the spring. We can use Hooke's law, which states that the force exerted by a spring is proportional to the displacement from its equilibrium position. The formula for Hooke's law is:

F = -kx

Where F is the force exerted by the spring, k is the spring constant, and x is the displacement from the equilibrium position. From the given information, we have:

F = 0.5 kg * g

Where g is the acceleration due to gravity (approximately 9.8 m/s^2). Now, let's find the displacement in meters:

x = 5 cm = 0.05 m

Plugging these values into Hooke's law:

-0.5 kg * g = -k * 0.05 m

We can solve for k:

k = (0.5 kg * g) / 0.05 m

Now that we have the spring constant, we can determine the potential energy (PE) stored in the spring when the mass is displaced. The formula for potential energy in a spring is:

PE = (1/2) * k * x^2

Plugging in the values:

PE = (1/2) * k * (0.05 m)^2

Next, let's find the kinetic energy (KE) of the mass as it passes through the equilibrium position. The formula for kinetic energy is:

KE = (1/2) * m * v^2

Where m is the mass of the object and v is its velocity. Given that the mass is 0.5 kg and the velocity is 50 cm/s, we need to convert the velocity to m/s:

v = 50 cm/s = 0.5 m/s

Plugging in the values:

KE = (1/2) * 0.5 kg * (0.5 m/s)^2

Now, according to the law of energy conservation, the total mechanical energy remains constant in a system. Therefore, the sum of potential and kinetic energy at any point in time should be equal to the initial total energy:

PE + KE = Total Energy

Substituting the formulas for PE and KE:

(1/2) * k * (0.05 m)^2 + (1/2) * 0.5 kg * (0.5 m/s)^2 = Total Energy

Now, you can plug in the values for k, m, and v to solve for the Total Energy. Once you have the Total Energy, you can use it to find the maximum displacement or any other information about the system.