Answer:
Nucleus A with 7 protons and 7 neutrons and Nucleus C with 7 protons and 5 neutrons are isotopes of the same elements
Explanation:
Isotopes are elements that have the same atomic structure but different molecular structure. An atom that has the same atomic number but different mass number are known to be isotopes.
The proton of an atom is the same as its atomic number while the sum of the proton and neutron is equal to its mass number.
According to the question, nuclei that has the same number of proton are isotopes of the same element. Therefore nuclei A and C with 7 protons each are isotopes of the same element since they have the same atomic number i.e number of proton = atomic number. 
Their atomic masses of nuclei A and C are 14 and 12 respectively
 
        
             
        
        
        
Answer:
Speed of the wave is 7.87 m/s.
Explanation:
It is given that, tapping the surface of a pan
of water generates 17.5 waves per second
We know that the number of waves per
second is called the frequency of a wave.
So, f= 17.5 HZ
Wavelength of each wave,
A = 45 cm = 0.45 m
Speed of the wave is given by:
175 × 0.45
V= 7.87 m/s
So, the speed of the wave is 7.87 m/s
Hence, this is the required solution.
        
             
        
        
        
Answer:
 energy is equal to 1000 J
Explanation:
When the jumper is in the tent, he has a given height, this height gives him a gravitational potential energy, which forms his initial mechanical energy of 1000 J. After jumping, this energy is converted into elastic energy of the rope plus a remainder of potential energy gravitational, it does not reach the ground, but as the friction is negligible the total mechanical energy is conserved, therefore its energy is equal to 1000 J
This is a case of energy transformation, but the total value of mechanical energy does not change
           
 
        
             
        
        
        
Answer:
Lithium and Sodium
Explanation:
Lithium and Sodium is in the same group 1A
 
        
             
        
        
        
Answer:
437.5Kjoules
Explanation:
K.E=half multiply by mass multiply by square of velocity 
=437.5Kjoules