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.
Answer: D) helium.
Explanation:
Nuclear fission is a process which involves the conversion of a heavier nuclei into two or more small and stable nuclei along with the release of energy.

Nuclear fusion is a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.
Example: 
Thus when deuterium and tritium , the two isotopes of hydrogen are fused, a heavier nuclei helium is being formed from two smaller nuclei releasing a neutron.
B. False
Stability is determined by the ratio of neutrons and protons. Electrons are not in nucleus.
Answer:
Yes
Explanation:
There is a difference between the homogeneous mixture of the hydrogen and the oxygen in a 2:1 ratio and the sample of the water vapor.
In the homogeneous mixture of the hydrogen and the oxygen which are present in the ratio, 2:1 , the elements are not chemically combined. They are explosive also as both shows their specific properties. They can be separated by physical means (Condensation, diffusion).
On the other hand, in water vapor, the two elements are chemically bonded in a specific mixture which cannot be separated via physical means. Water has its unique properties and they can be separated by chemical means only.