Answer:
The second dart leaves the gun two times as faster than the first one.
Explanation:
Assuming no energy loss during the spring-dart energy transfer, we have by the conservation of energy principle

Given an arbitrary
and its double,
, launch velocities are

The answer would be B. :)
I believe that a light bulb releases visible light and a radio antenna releases a radio waves
m = Q(on moon) * G(on moon) = 200N * 1.63N/kg = 326kg
Q(Earth)= g * m = 10m/s2 * 326kg = 3260N
F=ma
8480=26.5m
m=8480/26.5
m=320
The mass of the cart is 320kg.