Answer: 539.4 N
Explanation:
Let's begin by explaining that Coulomb's Law establishes the following:
"The electrostatic force 
between two point charges 
and 
is proportional to the product of the charges and inversely proportional to the square of the distance 
that separates them, and has the direction of the line that joins them"
What is written above is expressed mathematically as follows:
(1)
Where:
is the electrostatic force
is the Coulomb's constant
and are the electric charges
is the separation distance between the charges
Then:
(2)
Isolating and :
(3)
Now, if we keep the same charges but we decrease the distance to 
, (1) is rewritten as:
(4)
Then, the new electrostatic force will be:
(5) As we can see, the electrostatic force is increased when we decrease the distance between the charges.
Answer:
Option D
670 Kg.m/s
Explanation:
Initial momentum is given by mv=82*5.6=459.2 Kg.m/s (taking eastward as positive)
Final momentum is also mv but v being westward direction, we take it negative
Final momentum=82*-2.5= -205 Kg.m/s
Change in momentum=Final momentum-Initial momentum=-205-459.2=-664.2 Kg.m/s
Impulse=change in momentum=664.2 Kg.m/s rounded off as 670 Kg.m/s
There water has a lot of salt in it, so it would be denser. People float better when the water is denser.
Answer:
Definitely Spinning permanent magnets within an array of fixed permanent magnets
Explanation:
Any relative motion between magnets (be they permanent or electromagnetic) and a coil of wire will induce an electric current in the coil.
What will not induce an electric current is the relative motion between the two coils of wire (because there is no change in magnetic field), or the relative motion between two magnets (there are no coils of wire to induce the current into).
<em>Therefore, spinning permanent magnets within an array of fixed permanent magnets does not induce an electric current.</em>
