Without bending your arms at the elbow, try to lift a
book from the floor.Do you find it easy or difficult??
Please find below the answer:
Yes, it would be difficult or we can say impossible to pick to a book lying on the floor without bending our arm at the elbow. This is called elbow flexion. The forearm moves towards our body because elbows have hinge joints which will move a little when we lift a thing from the floor and need a certain amount of force for it.
Hope this clears your doubt.