Answer:
A. These vibrations can travel through solids, liquids, and gases, but not through <u>empty</u><u> </u><u>space</u>.
 
        
             
        
        
        
Given:
Momentum of the dog (p) = 120.5 kg m/s
Speed of the dog (v) = 5 m/s
To Find:
Mass of the dog (m)
Concept/Theory:

- It is defined as the quantity of motion contained in a body.
- It is measured as the product of mass of the body and it's speed.
- It is represented by p.
- It's SI unit is kg m/s
- Mathematical Representation/Equation of Momentum:  
Answer:
By using equation of momentum, we get:

 Mass of the dog (m) = 24.1 kg
 Mass of the dog (m) = 24.1 kg
 
        
             
        
        
        
In a closed system, the loss of momentum of one object  is same as________ the gain in momentum of another object
according to law of conservation of momentum, total momentum before and after collision in a closed system in absence of any net external force, remains conserved . that is 
total momentum before collision = total momentum after collision 
P₁ + P₂ = P'₁ + P'₂ 
where P₁ and P₂ are momentum before collision for object 1 and object 2 respectively.
P'₁ - P₁  = - (P'₂ -  P₂)
so clearly gain in momentum of one object is same as the loss of momentum of other object 
 
        
             
        
        
        
Answer:
A) Emin = eV
B) Vo = (E_light - Φ) ÷ e
Explanation:
A)
Energy of electron is the product of electron charge and the applied potential difference. 
The energy of an electron in this electric field with potential difference V will be eV. Since this is the least energy that the electron must reach to break out, then the minimum energy required by this electron will be;
Emin = eV
B)
The maximum stopping potential energy is eVo,
The energy of the electron due to the light is E_light. 
If the minimum energy electron must posses is Φ, then the minimum energy electron must have to reach the detectors will be equal to the energy of the light minus the maximum stopping potential energy
Φ = E_light - eVo
Therefore, 
eVo = E_light - Φ
Vo = (E_light - Φ) ÷ e
 
        
             
        
        
        
the answer choice will be A because they travel at the same speed through only light not one material.