1. The problem statement, all variables and given/known data A spring has a stiffness of 30 KN/m and supports a mass of 8 kg. The mass is pulled so that the spring t extends by amplitude of 10 mm and its released so that it produces linear oscillations . 2. Relevant equations (i) Determine the periodic time,circular frequency,and the natural frequency f. (ii) Calculate the maximum velocity of the mass.(iii) Calculate the maximum acceleration of the mass. 3. The attempt at a solution Periodic time; T = 1/f = (1 / 9.75) = 0.10260s Circular frequency; W= √ k / M w = √ 30000 / 8 = 61.24 rad/s Natural frequency; F = w / 2 π = 61.24 / (2π) = 9.75Hz Displacenent . 10 cos X (61.24 X 0.10260) = - 5.27 mm Which equations do I use ? Velocity = ωx sin ωt Or max velocity = x cos ωt =0 Acceleration= ω^2 x sin ωt Or max acceleration= x cos ωt If I am correct with displacement , it does not equal zero.Which is throwing me !