If the same net force is applied to a 7 kg object and a 21 kg object, then the 21 kg object accelerates three times faster than the 7 kg object. the 7 kg object accelerates three times faster than the 21 kg object. both objects accelerate at the same rate because the force is the same neither object will accelerate because there is a net force on the objects. What is the acceleration due to gravity on Mars?