Answer:
A. If the sum of the external forces on an object is zero, then the object must be in equilibrium
Explanation:
Equilibrium, in physics, the condition of a system when neither its state of motion nor its internal energy state tends to change with time.
For a single particle, equilibrium arises if the vector sum of all forces acting upon the particle is zero.
the object is at equilibrium, then the net force acting upon the object should be 0 Newton. Thus, if all the forces are added together as vectors, then the resultant force (the vector sum) should be 0 Newton.
There are three types of equilibrium: stable, unstable, and neutral
Answer:
b. Constant magnitude, but varying direction, perpendicular to the equipotential.
Explanation:
As we know that the relation between electric field and electric potential is given as

here if we say that potential is constant because electric field sensor is moving along equi-potential line.
Then we will say
V = constant
so we have

so electric field will remain constant always in magnitude and always remains perpendicular to the surface
so we have
b. Constant magnitude, but varying direction, perpendicular to the equipotential.
(d) Acceleration is a vector quantity
It’s a lot warmer now
Than it is during an ice age
Answer and Explanation:
The hydrogen atom is an atom of hydrogen element.Hydrogen atoms contain one proton which has positive charge and one electron which has negative charge , so due to positive and negative charge present in the hydrogen atom its becomes neutral atom.In whole universe the hydrogen atom is found in most abundant. Electron and nucleus of the hydrogen atom is bound together with the help of coulomb force.