Answer:
Chemical energy, Energy stored in the bonds of chemical compounds. Chemical energy may be released during a chemical reaction, often in the form of heat; such reactions are called exothermic.
 
        
             
        
        
        
Steel is more dense because it’s heavy while water is light
        
                    
             
        
        
        
Answer:
The particle’s velocity is -16.9 m/s.
Explanation:
Given that,
Initial velocity of particle in negative x direction= 4.91 m/s
Time = 12.9 s
Final velocity of particle in positive x direction= 7.12 m/s
Before 12.4 sec,
Velocity of particle in negative x direction= 5.32 m/s
We need to calculate the acceleration
Using equation of motion


Where, v = final velocity
u = initial velocity
t = time
Put the value into the equation


We need to calculate the initial speed of the particle
Using equation of motion again


Put the value into the formula


Hence, The particle’s velocity is -16.9 m/s.
 
        
             
        
        
        
Answer
given,
mass of the ball = 3 kg
swing in vertical circle with radius = 2 m
    work done by the gravity = ?          
    work done by the tension = ?            
Work done by the gravity = - m g Δh            
  Δ h = 2 + 2 = 4 m                                                                
Work done by the gravity =
                                            = -117.6 J                  
work done by gravity is equal to -117.6 J            
Work done by tension will be equal to zero.         
Zero because tension is always perpendicular to velocity 
work done by tension is equal to 0 J                          
 
        
             
        
        
        
Of the materials listed wood is the best insulator. It would be the least hot if exposed to similar temperatures.