The First Law describes how an object acts when no force is acting upon it. So, rockets stay still until a force is applied to move them. Likewise, once they're in motion, they won't stop until a force is applied. Newton's Second Law tells us that the more mass an object has, the more force is needed to move it. A larger rocket will need stronger forces (eg. more fuel) to make it accelerate. The space shuttles required seven pounds of fuel for every pound of payload they carry. Newton's Third Law states that "every action has an equal and opposite reaction". In a rocket, burning fuel creates a push on the front of the rocket pushing it forward.
Answer:

Explanation:
<u>Coulomb's Law</u>
The force between two charged particles of charges q1 and q2 separated by a distance d is given by the Coulomb's Law formula:

Where:

q1, q2 = the objects' charge
d= The distance between the objects
We know both charges are identical, i.e. q1=q2=q. This reduces the formula to:

Since we know the force F=1 N and the distance d=1 m, let's find the common charge of the spheres solving for q:

Substituting values:


This charge corresponds to a number of electrons given by the elementary charge of the electron:

Thus, the charge of any of the spheres is:


Answer:
The amount of work done required to stretch spring by additional 4 cm is 64 J.
Explanation:
The energy used for stretching spring is given by the relation :
.......(1)
Here k is spring constant and x is the displacement of spring from its equilibrium position.
For stretch spring by 2.0 cm or 0.02 m, we need 8.0 J of energy. Hence, substitute the suitable values in equation (1).

k = 4 x 10⁴ N/m
Energy needed to stretch a spring by 6.0 cm can be determine by the equation (1).
Substitute 0.06 m for x and 4 x 10⁴ N/m for k in equation (1).

E = 72 J
But we already have 8.0 J. So, the extra energy needed to stretch spring by additional 4 cm is :
E = ( 72 - 8 ) J = 64 J
The Electromagnetic and Visible Spectra. I believe..
The answer is Hertz (Hz) named in honor of the German scientist Heinrich Hertz, who first conclusively proved the existence of electromagnetic waves.