1. The problem statement, all variables and given/known data (a) A large spring has one end attached to the floor and a platform attached to its upper end. On the platform is placed a mass of 30 kg. The mass of the platform itself is 10kg. The spring-platform-mass system is then set into vertical oscillations with a period of 1.5 s. Determine (i) the stiffness (spring constant) of the spring (ii) the amplitude of the motion if the maximum speed of the mass is 1 ms-1. (b) (i) If the motion of the mass (in part (a)) is timed starting from its highest point, calculate how far it has travelled in 1.3 s 2. Relevant equations x= A cos (wt) 3. The attempt at a solution The answer must be x= 0.88m I've solved part a) already k= 705.6 N/m w= 4.2 rad/s A= 0.24 m but I'm struggling in part b) Can someone help me using the formula x= A cos (wt) PS: This is a past exam paper, I'm using it to study and practice for my exam.