To increase the number of snowmen destroyed, you would want more energy and all of the above would increase the energy of the system so D.
Replaces spring 2. the mass of the weight and pulley are unchanged: m=5.8 kg and mp=1.7 kg
Answer:

Explanation:
Ok, the average speed can be calculate with the next equation:
(1)
Basically the car cover the same distance "d" two times, but at different speeds, so:

and the total time would be the time t1 required to go from A to B plus the time t2 required to go back from B to A:

From basic physics we know:

so:


Using the previous information in equation (1)

Factoring:
(2)
Finally, replacing the data in (2)

Frequency = velocity/wavelength
Frequency = 10/20
Frequency = 0.5 Hz