Consider the following statements:
The basic reason why shafts are made of steel and its alloys is:
1. The shaft is subjected to normal stress.
2. The shaft stress alternates with respect to time.
3. The shaft is subjected to pure compressive stress.
4. The shaft is subjected to the stress of constant intensity.
Which of these statements are correct?
1. 1 and 2
2. 2 and 3
3. 3 and 4
4. 4 and 1
5.