Yea I think the light is to fast
Kinetic energy=Ek
Ek=(1/2)mv²
Ek=480 J
v=8 m/s
mass=?
Ek=(1/2)mv²
480 J=(1/2)m(8 m/s)²
480 J=(32 m²/s²) m
m=(480 J)/(32 m²/s²)=15 kg
answer: the mass of the object is 15 kilograms.
I would expect fine salt to fully dissolve by the end of 45 minutes. Since the other types of salt are not fine and tiny, they would take longer to dissolve
The method is called the displacement method.
You place some water in the graduated cylinder and measure its volume.
Then you add your object and measure the new volume.
The difference between the two volumes is the volume of your object.
The violet light is the answer!