Which one of the following statements concerning the momentum of a system when the net force acting on the system is equal to zero newtons is true? a. The momentum of the system is increasing.
b. The momentum of the system is decreasing.
c. The momentum of the system is equal to zero kg .m/s.
d. The momentum of the system has a constant value.
e. The momentum of the system has a negative value.

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600