Answer:
A) 11.28 x 10^(7) A.m² 
B) 2.258 x 10^(17)A
Explanation:
A) The current density is given by the formula ;
J = nqv
Where n is the density of protons in the solar wind which is 12.5 cm³ or 12.5 x 10^(-6) m³ 
q is the proton charge which is 1.6 x 10^(-19) C
v is velocity which is 564km or 564000m
Thus, J = 12.5 x 10^(-6) x 1.6 x 10^(-19) x 564000 = 11.28 x 10^(7) A.m²
B) the formula for the total current the earth received is given as;
I = JA
The effective area is the cross section of the earth and thus,
Area = πr² where r is the radius of the earth given as: 6.371 x 10^(6)
A = π(6.371 x 10^(6)) ²
So I = 11.28 x 10^(7) x π(6.371 x 10^(6))² = 2.258 x 10^(17)A
 
        
             
        
        
        
Answer:
2. decreasing the distance of the space shuttle from Earth
Explanation:
To increase the gravitational force on a space shuttle, it is a good thing to decrease the distance of the space shuttle from the earth. 
This is based on the Newton's law of universal gravitation which states that "the gravitational force between two bodies is a directly proportional to the product of their masses and inversely proportional to the square of the distance between them". 
  Mathematically; 
            F  =  
  
G is the universal gravitation constant, it cannot be changed
m is the mass of the body
r is the distance 
   Since the distance is inversely proportional, is we reduce it, the value of the gravitational force will increase. 
 
        
                    
             
        
        
        
Answer:
If T^2 = a^3
T1^2 / T2^2 = a1^3 / a2^3
Or T2^2 = T1^2 * ( a2^3 / a1^3)
Given T1 = 1 yr and a2 / a1 = 17
Then T2^2 = 1 * 17^3
or T2 = 70 yrs
 
        
             
        
        
        
-- The net effective resistance of three 1200-ohm resistors in 
parallel is (1200/3) = 400 ohms.  That's what the battery sees.
-- Power = (voltage)² / (resistance)
               =      (12²)    /      (400)
               =        144    /      400
               =             0.36 watt .  
There's no such thing as "power in the circuit".
0.36 watt is the power dissipated by the resistors.
It's the rate at which the battery must supply energy,
and the rate at which the resistors blow it off in the form
of heat, for as long as the battery lasts.