The mechanism above is a harmonic oscillator. It consists of two identical spheres connected by a massless spring. The two masses translate toward and away from each other and the entire system spins about its center of mass. Assume that there is no relative rotation between masses A and B. You may also assume the center of mass of the system has no velocity. Do not model the masses as particles. Do not include friction. Do not include gravity

pecialized keyboards

none, its a machine

that would be b i just took the test : )

the correct answers are:

ab ⇒ not moving

bc ⇒ positive acceleration

cd ⇒ constant velocity

de ⇒ not moving

ef ⇒ negative acceleration

explanation:

assumption: let me assume that the horizontal axis represents the time (as the image is cropped from below). [i know, although, that it is time in x-axis] in that case, it is a position vs. time graph.

first, as you can see in the graph that from point a to point b, the position of the body is same. to be more precise, as you can see in the interval 0-20, the position is 20 meters at every point, which means that the body is not moving. hence, the path ab corresponds to not moving.

second, from point b to c, as you can see that the position of a body from intervel 20 to (about) 35, the position of a body has started changing slowly from the "not moving" state; however, between 35 and 40, the position changes rapidly, which means that the velocity of the body is increasing. if the velocity of the body increases, there will be a positive acceleration. hence, the path bc corresponds to positive acceleration.

third, from point c to d, the position of a body is changing constantly. it means that there will be a constant velocity from point c to point d. hence, the path cd corresponds to constant velocity.

fourth, from point d to e, the position is again not changing. it means that the body is in not moving state. hence, the path de corresponds to not moving.

last, from point e to f, as you can see, the body's position is changing rapidly at start, but after about 85 (seconds), the position is changing slowly, which means that the velocity of the body is decreasing. if the velocity of the body is decreasing, there will be a negative acceleration. hence, the path ef corresponds to negative acceleration.