What class lever is a screw?

Answer 1

The biceps brachii acts as a class 3 lever to flex the arm. The deltoid also acts as a class 3 lever to abduct the arm, as does the teres major in adducting the arm. The triceps brachii, however, acts as a class 1 lever to extend the arm. In other words, when you're bending your arm or swinging it toward your body or away from your body, it's a class 3 lever. But if your arm is bent and you're straightening it, then your arm is a class 1 lever.

Answer 2

Its a slightly difficult one as we could argue that the load and pivot are in the same place. If we take the pivot as being at the centre of the bolt and the load at the outside of the bolt then it is a second class lever. Pivot-Load-Effort

Answer 3

In a common ratchet there is a load and pivot that is present. For this type of ratchet it would be classified as a second class lever.

Answer 4

third

Answer 5

First Class