Question

Consider the spring-mass system, with the mass submerged in water, as shown in the figure. The phase space diagram for one cycle of this system is

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

In all the given four figures, at mean position the position coordinate is zero. At the same time mass is starting from the extreme position in all four cases. In Fig. (c) and (d), extreme position is more than the initial extreme position. But due to viscosity opposite should be the case. Hence, the answer should be either option (a) or option (b). Correct answer is (b), because mass starts from positive extreme position (from uppermost position). Then, it will move downwards or momentum should be negative.