Explanation:
The Coulomb's law states that the magnitude of each of the electric forces between two point-at-rest charges is directly proportional to the product of the magnitude of both charges and inversely proportional to the square of the distance that separates them:

In this case we have an electron (-e) and a proton (e), so:

In this case, the electric force is negative, therefore, the force is repulsive and its magnitude is:

Water boiling is an example of a physical change. The rest are chemical changes.
Hope that helps!!
Answer:
A body will become positively charged when some electrons will come out from the body.Thus, positive charge is due to deficiency of electrons.
Answer:
2.75 m/s^2
Explanation:
The airplane's acceleration on the runway was 2.75 m/s^2
We can find the acceleration by using the equation: a = (v-u)/t
where a is acceleration, v is final velocity, u is initial velocity, and t is time.
In this case, v is 71 m/s, u is 0 m/s, and t is 26.1 s Therefore: a = (71-0)/26.1
a = 2.75 m/s^2
Boron Group
elements have three valence electrons and are fairly reactive. All of them are solids at room temperature. Boron is a very hard, black metalloid with a high melting point.