Answer:
I. Speed = 20m/s
II. Velocity = 20m/s due North.
Explanation:
<u>Given the following data;</u>
Distance = 40m
Time = 2secs
To find the speed;
Mathematically, speed is given by the formula;

Substituting into the equation, we have;

<em>Speed = 20m/s.</em>
In physics, we use the same formula for calculating speed and velocity. The only difference is that speed is a scalar quantity and as such has magnitude but no direction while velocity is a vector quantity and as such it has both magnitude and direction.

<em>Therefore, the velocity is 20m/s due North</em>.
Answer:
6.86 × 10²⁴ kg
Explanation:
The mass of the earth m = density of earth, ρ × volume of earth, V
m = ρV
The density of the earth, ρ = 5515 kg/m³ and since the earth is a sphere, its volume is the volume of a sphere V = 4πr³/3 where r = radius of the earth = 6.67 × 10⁶ m
Since m = ρV
m = ρ4πr³/3
So, substituting the values of the variables into the equation for the mass of the earth, m, we have
m = 5515 kg/m³ × 4π(6.67 × 10⁶ m)³/3
m = 5515 kg/m³ × 4π × 296.741 × 10¹⁸ m³/3
m = 5515 kg/m³ × 1189.9639π × 10¹⁸ m³/3
m = 6546105.64378π × 10¹⁸ kg/3
m = 20565197.400122 × 10¹⁸ kg/3
m = 6855065.8 × 10¹⁸ kg
m = 6.8550658 × 10²⁴ kg
m ≅ 6.86 × 10²⁴ kg
ELECTROSTATIC:
relating to stationary electric charges or fields as opposed to electric currents.
NEUTRAL:
nor negative nor positive/having no charge
POSITIVELY CHARGED:
positive charge occurs when the number of protons exceeds the number of electrons
NEGATIVELY CHARGED:
negative charge occurs when the number of electrons exceeds the number of protons.
COULOMB:
SI unit for electric charge. One coulomb is equal to the amount of charge from a current of one ampere flowing for one second.
MICROCOULOMB:
a unit of electrical charge equal to one millionth of a coulomb.
NANOCOULOMB:
Nanocoulombs are a unit of charge 1,000,000,000 times smaller than Coulomb.
CONSERVATION OF CHARGE:
constancy of the total electric charge in the universe or in any specific chemical or nuclear reaction
QUANTISATION OF CHARGE:
Charge quantization is the principle that the charge of any object is an integer multiple of the elementary charge.