Answer:
The forces creating the net force must lie in the same direction.
Explanation:
newton's second law states that the net force acting on the body is equal to the product of mass and the acceleration of the body.
If there are several forces acting on the body in different directions, then we have to find teh net force by using the vector sum and then find the acceleration.
It is not necessary that all the forces acting in the same direction.
if they are in different directions then we have to find the net force by t=using the formula for the vector sum.
Answer A is incorrect
A crest is just one point. It is not the distance between 2 crests.
B is incorrect
A trough is just 1 point. It is not the distance between 2 troughs.
C is incorrect.
the amplitude measures the height of a crest from the middle of the wave to the crest (or trough).
D is the correct answer. That is the distance between 2 crests or 2 troughs
Continuous. Discrete values are values like 1, 2, 3, 4, etc. - they're values that are <em>distinct</em>, and typically there's some idea of a <em>next </em>and a <em>previous </em>value. When we're counting whole numbers, there's a definitive answer to which number comes after, and which number comes before. With continuous values, there's no real "next" or "last" value.
Motion is measured with <em>continuous </em>values; a train might move 300 yards in 1 minute, but we can look at smaller and smaller chunks of time to keep getting shorter and shorter distances. There is no <em />"next" distance the train moves after those 300 yards - it just doesn't make sense for there to be.
It's also measured <em>quantitatively</em>, not <em>qualitatively</em>. This just means that we can use numerical values to measure it, rather than other descriptors like color, smell, or taste.