A student was sitting motionless in class. Which of the following explains why the student remains motionless? A - There are no forces acting on the student.
B - The only force acting on the student is gravity pulling down.
C - The forces acting on the student are balanced.
D - The chair is the only force acting on the student, keeping them still.

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