Answer: Option A
Explanation:
The potential energy decreases in the case when the charges are opposite and they attract each other.
In this case there is no external energy required in order to put the charges together.
This is so because the charges are opposite and they will attract each other. Yes, the only condition should be that the charges should be alike.
Example: a negative charge and a positive charge.
 
        
             
        
        
        
The Canadian Shield<span>, also called the Laurentian Plateau, or Bouclier canadien (French), is a large area of exposed Precambrian igneous and high-grade metamorphic </span>rocks<span> (geological </span>shield<span>) that forms the ancient geological core of the North American continent (the North American Craton or Laurentia).</span>
        
             
        
        
        
Answer:
136000 J or 136 kJ
Explanation:
Formula
Heat = m * c * deltaH
Givens
m= 0.5 kg
c = 3400 J / (kg * oC)
Deltat = (100oC - 20oC)
deltat = 80oC
Solution
Heat = 0.5 kg * 3400 J/(kg* oC) * 80oC
Heat = 136000 Joules
Heat = 136 kg
Technically there is only 1 place of accuracy.
 
        
             
        
        
        
Answer:
2960 N
Explanation:
Convert rev/min to rad/s:
150 rev/min × (2π rad/rev) × (1 min / 60 s) = 50π rad/s
Sum of forces in the centripetal direction:
∑F = ma
T = m v² / r
T = m ω² r
T = (0.2 kg) (50π rad/s)² (0.6 m)
T = 2960 N