The inertial mass of an object determines its acceleration in the presence of an applied force. According to Newton's second law of motion, if a body of fixed mass M is subjected to a force F, its acceleration α is given by F/M. A body's mass also determines the degree to which it generates or is affected by a gravitational field. If a first body of mass MA is placed at a distance R from a second body of mass MB, each body experiences an attractive force Fg = GMAMBR/|R|3, where G=6.67×10−11 N kg−2m2 is the "universal gravitational constant". This is sometimes referred to as gravitational mass.[note 1] Repeated experiments since the 17th century have demonstrated that inertial and gravitational mass are equivalent