An object is attached to a vertical ideal massless spring and bobs up and down between the two extreme points A and B. When the kinetic energy of the object is a minimum, the object is located
A) at either A or B.
B) midway between A and B.
C) 1/3 of the distance from A to B.
D) 1/4 of the distance from A to B.
E) 1/ times the distance from A to B.

Question

An object is attached to a vertical ideal massless spring and bobs up and down between the two extreme points A and B. When the kinetic energy of the object is a minimum, the object is located
A) at either A or B. 
B) midway between A and B. 
C) 1/3 of the distance from A to B. 
D) 1/4 of the distance from A to B. 
E) 1/ times the distance from A to B.

Quizplus · Accepted Answer

When the object is at either A or B, it reaches its maximum potential energy and minimum kinetic energy. At any other point, the object has both potential and kinetic energy, and the kinetic energy is not at its minimum. Therefore, the object must be located at either A or B when its kinetic energy is a minimum.

An Object Is Attached to a Vertical Ideal Massless Spring