Answer:
D. Both occur between objects independently whether they are in contact  or not.
Explanation:
- The gravitational force is a force that is exerted between two (or more) objects having mass. This force is always attractive and its magnitude is given by

where G is the gravitational constant, m1 and m2 are the two masses, and r is the distance between the two masses.
- The electrical force is a force that is exerted between two (or more) objects having electrical charge. It can be either attractive or repulsive, depending on the sign of the two charges, and its magnitude is given by

where k is the Coulomb's constant, q1 and q2 are the two charges, and r the distance between the two charges.
Looking at both formulas, we see that the two forces are present even when the two objects are not in contact with each other (in fact, r can assume any value in the formula). They are said to be non-contact forces. Therefore, the correct option is
D. Both occur between objects independently whether they are in contact  or not.
 
        
             
        
        
        
Explanation:
It is given that,
Average power per unit mass generated by Lance, 

(a) Distance to cover race, 
Average speed of the person, v = 11 m/s
If t is the time taken to cover the race. 


t = 14545.46 s
Let W is the work done. The relation between the work done and the power is given by :



W = 7090911.75 J
(b) Since, 
So, in 7090911.75 J, 
W = 1694.01 J
Hence, this is the required solution.
 
        
             
        
        
        
The formula that is applicable here is E = kQ/r^2 in which the energy of attraction is proportional to the charges and inversely proportional to the square of the distance. In this case, 
kQ1/(r1)^2 = kQ2/(r2)^2  r1=l/3, r2=2l/3solve Q1/Q2
kQ1/(l/3)^2 = kQ2/(2l/3)^2  kQ1/(l^2/9) = kQ2/(4l^2/9)Q1/Q2 =   1/4
        
                    
             
        
        
        
1. The correct answer among the choices provided is the third option. Measuring the temperature increase of water from doing work by stirring it is an experiment generally regarded as being first carried out by James Joule.
2.  Joule's experiment directly shows that heat is a form of energy. He wanted to make a different way of measuring energy.