<u>Answer </u>
Wind
Water movement
A hill
<u>Explanation. </u>
The question does not specify it is the acceleration of what is to be accelerated. So my answer will be general. Acceleration is the change of velocity with time.
Wind can cause acceleration of sound. If the sound is travelling in the direction of sound, its speed wound increase. The reverse is also true.
Water movement can also cause acceleration. When a bout is moving in the direction of water movement, then it will be expected that the resultant speed of the bout to be higher. If the bout was moving against the water movement, its speed would be decreased.
A hill would reduce the speed of a moving vehicle. This is also an acceleration that is negative (deceleration).
A stop light and a flat road cannot cause acceleration.
Answer:
The valence electrons determine an atom's reactivity.
Explanation:
The valence electrons is the electrons on the most outer layer of an atom. The higher the number of valence electrons, the bigger the reactivity of the atom. This means that when that atom is put with another substance and it reacts, it would react in a much more violent way than another atom with lower valence electrons.
About 80 percent of sun reach earth surface
Let the ball is initially at point P1. Finally it reaches at point P2.( bottom most). Since only conservative force is acting on the ball throughout the motion, mechanical energy will be conserved. Therefore conserving energy from P1 to P2,
Initially ball is at rest(P1). So initial kinetic energy is 0. Let ball is at height h1 initially, so initial potential energy = mgh ( m= mass of the ball). At bottom most point (P2), potential energy of ball changes into kinetic energy. So final kinetic energy =1/2 mv^2. Final potential energy = 0. Equating energies at P1 and P2,
Mgh= 1/2 mv^2. Therefore, v= (2gh)^1/2. Since all the initial and final points are at same height, velocity will be same for all the paths(irrespective of the path taken by ball). So velocity will be same.
In physics, work is defined as the total energy when an object is moved to a certain displacement by the application of external force. It is calculated by the expression W = Fd. For this case, the displacement is apparently zero, then there is no work in the system above.