Physics 1501q - lecture 12 - linear statics and momentum 9/21/18. Key (in si units): t = time (s) x = distance (m) v = velocity (m/s) a = acceleration (m/s 2 ) = change in g = gravity = 9. 81 m/s 2 m = mass (kg) When an object is in translational equilibrium, the net force acting on it is 0. F = 0 (source: slide 9 on 9/21 lecture notes https://lms. uconn. edu/bbcswebdav/pid-2538787-dt-content-rid-38406101_1/courses/1188-uco. No force is applied, and therefore there is no movement. Then, we move the spring-mass to the right by a distance a: The restoring force, f, can be defined as equal to -k x according to hooke"s law: If we let go of the spring-mass, it will have a velocity in the direction of the spring: Then, the spring-mass will reach x = -a before springing back in the initial direction and past the equilibrium position: