Explanation:
In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. It is the macroscopic energy associated with a system. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is constant. If an object moves in the opposite direction of a conservative net force, the potential energy will increase; and if the speed (not the velocity) of the object changes, the kinetic energy of the object also changes. In all real systems, however, nonconservative forces, such as frictional forces, will be present, but if they are of negligible magnitude, the mechanical energy changes little and its conservation is a useful approximation. In elastic collisions, the kinetic energy is conserved, but in inelastic collisions some mechanical energy may be converted into thermal energy. The equivalence between lost mechanical energy (dissipation) and an increase in temperature was discovered by James Prescott Joule.
Answer: A) highly mobile electrons in the valence shell
Explanation: conductivity in metals is a result of the movement of electrically charged particles—the electrons. These free electrons also known as valence electrons are free to move, and as a result they can travel through the lattice that forms the physical structure of a metal. The presence of valence electrons determines a metal's conductivity. However, several other factors can affect the conductivity of a metal such as impurities, temperature, magnetic fields etc.
Answer:
No. Because it would correspond to zero Instantaneous acceleration.
Explanation:
hope this helps
Light is a form of energy.
(:
Answer: 
Explanation:
According to Newton's law of Gravitation, the force 
exerted between two bodies of masses 
and 
and separated by a distance 
is equal to the product of their masses and inversely proportional to the square of the distance:
(1)
Where:
is the Gravitational Constant and its value is 
is the mass of the Sun
is the mass of the Earth
is the distance between the Sun and the Earth
Substituting the values in (1):
(2)
Finally:
This is the gravitational force acting on the earth due to the sun
