A student tries to raise a chain consisting of three identical links. Each link has a mass of 240 gram. The three piece chain is connected to a string and then suspended vertically, with the student holding the upper end of the string and pulling upward. Because of the student's pull, an upward force of 16 Newton is applied to the chain by the string. Use Newton's laws:
Determine the acceleration of the chain.
Obtain the force exerted by the top link on the middle link.