The action of the biceps brachii muscle on the hinge joint of the elbow is an example of which kind of lever system?

a. First class

b. Second class

c. Third class

d. Fourth class

Video transcript

Hey, everyone. Let's take a look at this question together. Which of the following is an example of a first class lever in the human body. Is it answer choice? A standing on toes, answer choice B pushing a wheelbarrow. Answer choice, C tipping the head backward or answer choice. D all of the above. Let's work this problem out together to, to figure out which of the following answer choices is an example of a first class lever in the human body. So in order to solve this question, we have to recall what a first class lever is and what type of lever each of the following answer choices is. And here we have an image on the screen depicting a first class lever where we have the full found in the middle of effort and load. And we know that the fulcrum is between the effort, which is the applied force and the resistance, which is the load and a first class lever in the head. For example, tipping the head backward where our fulcrum is the joint between the skull and the spine. The effort is the muscles at the back of the neck and the load is the weight of the head. So the fulcrum which is in between the effort and the load is that joint that is between the skull and the spine found between the effort, which is the muscles at the back of the neck and the load, which is the weight of the head. So an example of a first class lover in the human body is answer choice. C tipping the head backward and answer choice A and B are both incorrect since standing on toes and pushing a wheelbarrow are both examples of second class levers where the load is found between the fulcrum and the applied force. So answer choice C is the only correct answer choice. I hope you found this video to be helpful. Thank you and goodbye.