Find the instantaneous velocity of a mass on a spring oscillating on a horizontal frictionless surface at the instant when its displacement is half of its maximum displacement x=(x_max/2). Assume the max velocity of that mass during each oscillation is v_max= 2m/s.

I know that I will have this: v = (2*pi)/T *(x_max/2) I'm having trouble because I don't have the period(T). I also don't know x_max

You don't need to know the period. The sum of the kinetic (1/2) M V^2 and potential energy (1/2) kX^2 is constant. When X is half the maximum value, the P.E. is 1/4 of the maximum value. That means the kinetic energy is 3/4 of its maximum value, since energy shifts from all-kinetic to all-potential.

The maximum KE is (1/2)MV-max^2 . When it is 3/4 of that, V^2 = 3/4 V-max^2
V = sqrt(3/2) V_max = sqrt 3 m/s

To find the instantaneous velocity of the mass on a spring, we can use the equation:

v = (2 * π / T) * x

Where v represents the instantaneous velocity, T is the period of oscillation, and x is the displacement of the mass at that instant.

In this case, we are given that the maximum velocity of the mass is v_max = 2 m/s. We can relate the maximum velocity and the maximum displacement to the period:

v_max = (2 * π / T) * x_max

Since we are given v_max = 2 m/s, we can rearrange the equation to solve for T:

2 = (2 * π / T) * x_max

We are also given that the displacement at the instant of interest is x = (x_max / 2). Substituting this into the equation, we have:

2 = (2 * π / T) * (x_max / 2)

Simplifying, we get:

2 = (π / T) * x_max

Now, let's solve for T:

T = (π / x_max) * 2

We still don't know the value of x_max, which represents the maximum displacement of the mass on the spring. This information is not provided in the problem statement, so we cannot determine the exact value of T without it. However, if you have the value of x_max, you can substitute it into the equation to find T.

Once you have the value of T, you can substitute it and the given value of x = (x_max / 2) into the original equation to find the instantaneous velocity.