<span>A. crest, crest
hope im right!(: </span>
Answer:
(A) 
Explanation:
The net force perpendicular to the surface of the incline is the sum of the gravity force component, which is mgcos(theta), and the reactionary normal force caused by the surface of the incline. The sum is F_N - mgcos(theta) and is usually 0 which is why the object is not moving perpendicularly to the surface of the incline.
Answer:
D. Friction and air resistance created heat on his trip up the hill.
Explanation:
Energy transformation from one form to another is not 100% efficient. This is the postulate of the first law of thermodynamics.
Most of the energy transformation is not purely 100%.
When energy is transformed, some are usually wasted.
- In this case, in moving from bottom up, Superman produced some heat and encountered air resistance.
- To reach the top, he must have overcome the resistance and produce enough heat to power him through.
- This reduces the amount of potential energy that should have been the same as the kinetic energy down below.
The answer is C. Watson and Crick developed the Double Helix model seen in the diagram.
