In physics, force is what causes a mass to accelerate. It may be experienced as a twist, a push, or a pull. The acceleration of a body is proportional to the vector sum of all forces acting on it (known as the net force or resultant force). In an extended body, force may also cause rotation, deformation, or an increase in pressure for the body. Rotational effects are determined by the torques, while deformation and pressure are determined by the stresses that the forces create