Consider a cart at rest at the bottom of a slope. It rests on a compressed spring. What is the initial energy of the cart in terms of potential and kinetic energy. Is the described system completely closed

In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity.