Answer:
The distance is 1.69 m.
Explanation:
Given that,
First charge 
Second charge 
Distance = 3.25 m
We need to calculate the distance
Using formula of electric field





Put the value into the formula





Hence, The distance is 1.69 m.
Answer:
After 4 s of passing through the intersection, the train travels with 57.6 m/s
Solution:
As per the question:
Suppose the distance to the south of the crossing watching the east bound train be x = 70 m
Also, the east bound travels as a function of time and can be given as:
y(t) = 60t
Now,
To calculate the speed, z(t) of the train as it passes through the intersection:
Since, the road cross at right angles, thus by Pythagoras theorem:


Now, differentiate the above eqn w.r.t 't':


For t = 4 s:

If I remember correctly, it is the 3rd answer choice.
Answer:
2Mg + O2 = Reactant | 2MgO = Product
Explanation:
It is pretty simple, look:
The elements that are being added (or in the majority of the cases, the one who are in the left side) are always the Reactant.
The other side is the product of the reactants.
It is like a mathematic formula
We some the numbers to get the result, the numbers are the reactants and the result is the product.
(I hope you didn´t get confused)