I have encountered two separate review problems that have to do with finding a value for amplitude and I am really struggling with it. 1. The problem statement, all variables and given/known data Question 1- A mass of 3kg is free to move on a horizontal frictionless surface and attached to a spring of k=15 N/m. It is displaced from equilibrium by 0.1m to the right and released from rest. What is the amplitude of the oscillation ? Question 2- A simple pendulum consists of a 4kg mass attached to a 3m long rope. At t=0 it is moving to the right at 0.4m/s. What is the maximum angle to which it swings? 2. Relevant equations (1) x=Acos(wt+θ) (2) v=-wAsin(wt+θ) 3. The attempt at a solution Question 1- I assumed the amplitude was equal to 0.1m from the question however I have a lot of trouble justifying it to myself. If this is intact the case I would really appreciate an explanation as to why, if not some insight on how to find A would be very helpful. Question 2- I attempted to solve for A using equation 2 and the information given regarding t=0 but ran into the issue of not knowing the value of θ, and have kind of hit a road block now.