Answer:
Real images are formed where rays of light actually converge, whereas virtual images occur with they are perceived to converge. Real images can be produced by passing light through converging lenses or with a concave mirror of some sort.
Explanation:
hope that helped a little :)
Answer:
it is a measure of the heat content of fuels or energy sources
Explanation:
<span>vibrations that travel through the air or another medium and can be heard when they reach a person's or animal's ear.</span>
Answer:
The answer is b, friction.
Explanation:
Let's say you're riding your roller skates on the sidewalk. The surface of the sidewalk rubs against your skates, counteracting your movement while you proceed in the opposite direction that the sidewalk is counteracting. The force that causes that is friction.