Question

In an oscillating spring mass system, a spring is connected to a box filled with sand. As the box oscillates, sand leaks slowly out of the box vertically so that the average frequency ω(t) and average amplitude A(t) of the system change with time t. Which one of the following options schematically depicts these changes correctly? 

• A. Figure 1
• B. Figure 2
• C. Figure 3
• D. Figure 4

Hint:

Frequency of a spring-mass system is inversely proportional to the square root of the mass. Amplitude decreases due to energy loss from damping or mass leaving the system.