Density reduces
Explanation:
The density of a fluid will reduce as a substance gains more thermal energy. Heat is a form of thermal energy usually noticed as temperature differences in a matter. 
- When thermal energy is gained by a body, the temperature of the body rises. 
- The particles of the medium gains more kinetic energy. 
- This causes the substance to expand and it has more volume. 
- When a substance expands, it occupies more space. 
- The more the volume a body occupies, the lesser the density. 
- Expansion does not change the mass of the fluid but the volume changes. 
- This is why density decreases. 
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Density brainly.com/question/8441651
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The momentum p of a moving particle is the product between its mass, m, and tis velocity, v:

In our problem, we know 

 and 

, and using the relationship mentioned above, we can find the mass m of the particle:
 
 
        
        
        
Answer:
Waves; wavelength; electromagnetic energy; ultraviolet light.
Explanation:
Sound are mechanical waves that are highly dependent on matter for their propagation and transmission. 
Sound travels faster through solids than it does through either liquids or gases.
Light wave can be defined as an electromagnetic wave that do not require a medium of propagation for it to travel through a vacuum of space where no particles exist.
Hence, sound and light are both found as waves, with a variety of wavelength. The sun, a source of light waves specifically, releases a type of electromagnetic energy. It can be found as UVA or UVB types. These lights give off different levels of ultraviolet light, some of wich can be harmful. 
Additionally, the ultraviolet spectrum is divided into three categories and these are; UVA, UVB and UVC.
 
        
             
        
        
        
f' = frequency observed by the police car after sound reflected from the vehicle and comes back to police car = 1250 Hz 
f = frequency emitted by the police car  = 1200 Hz 
V = speed of sound = 340 m/s 
v = speed of vehicle = ?
frequency observed by the police car is given as 
f' = f (V + v)/(V - v)
inserting the values in the above equation 
1250 = 1200 (340 + v)/(340 - v)
v = 6.9 m/s 
 
        
                    
             
        
        
        
Answer:
the two factors are the mass of the objects and the coefficient of friction between them
Explanation:
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