Answer:
Solids
Explanation:
The speed of sound is different in different mediums. Among solids, liquids, and gases, sound travels faster through solids. The particles in solids are more closes as compared to liquids and gases.
As per Definition of acceleration we know that rate of change in velocity of object is known as acceleration

so when we apply push on an object that push or applied force will change the velocity of object always
so correct answer must be
a.) changed the velocity
Answer:
Frictional Force: Frictional force is the force caused by the relative motion of two surfaces that come into contact with each other.
Answer:
Work- Activity involving mental or physical effort done in order to achieve a purpose or result.
Explanation:
This was the first definition from the dictionary on google :)