1. Look at the automotive engine shown in the figure below.
Auto Technician A says that the each of the camshafts in this engine makes two revolutions for every one revolution of the crankshaft. Auto Technician B says that the camshafts in this engine rotate in the opposite direction from the crankshaft. Which one of the following statements is correct?
A. Only Technician A is correct.
B. Only Technician B is correct.
C. Both Technician A and Technician B are correct.
D. Neither Technician A nor Technician B is correct.
To determine the correct answer, we need to analyze the statements made by Auto Technicians A and B.
Technician A states that each of the camshafts in this engine makes two revolutions for every one revolution of the crankshaft. In a typical four-stroke engine, the camshaft rotates at half the speed of the crankshaft because it completes one full revolution for every two revolutions of the crankshaft. This is due to the fact that the camshaft is responsible for opening and closing the engine's valves, which only need to open and close once per every two revolutions of the crankshaft. Therefore, Technician A's statement is correct.
Technician B states that the camshafts in this engine rotate in the opposite direction from the crankshaft. To determine the accuracy of this statement, we need to understand the relationship between the crankshaft and the camshaft. In most engines, the camshaft and the crankshaft rotate in the same direction. This is because the camshaft relies on the rotation of the crankshaft to operate the valvetrain. However, there are some engines that use a "reverse rotation" camshaft, where the camshaft rotates in the opposite direction to the crankshaft. Without more specific information about the particular engine shown in the figure, Technician B's statement cannot be definitively deemed correct or incorrect.
Therefore, the correct answer is A. Only Technician A is correct.