A square-threaded screw jack is a mechanical device widely used for lifting heavy loads or applying considerable force. Its operation is based on converting the force applied at its handle into a torsional moment, causing the upward impending motion of the screw. This movement is accomplished by overcoming the static friction between the threads of the screw and the jack.
To better comprehend how a screw jack functions, consider the completely unraveled thread as a block in contact with the...

Anatomical movements refer to the various actions or motions that can be performed by the body's joints and muscles. These movements are described using specific terms to provide a standardized way of discussing and understanding the range of motion at different joints.
Here are some common anatomical movements:
Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal,...

Newton's third law states that every action has an equal and opposite reaction. Consider a swimmer pushing off the side of a pool. They push against the wall of the pool with their feet and accelerate in the direction opposite to that of their push. This occurs because the wall exerts an equal and opposite force on the swimmer. Here, the forces do not cancel out each other as they are acting on different systems. In this case, there are two systems: the swimmer and the wall. If we select the...

Newton's laws can be applied to bodies at rest and bodies in motion. Newton's first law is applied to bodies in equilibrium, whereas the second law applies to accelerating bodies. To study accelerating bodies, first, the directions and magnitudes of acceleration and the applied forces are determined. Then, the free-body diagram is constructed, and Newton's second law is applied, considering the components of the forces in the x and y directions.
Let's imagine a person is standing on a weighing...

When we observe objects around us, one question that comes to mind is why they move or stay still. The answer to this question can be explained using Newton's laws of motion. These laws describe the fundamental principles of motion and the effects of forces on objects.
The first law of motion, also known as the law of inertia, states that an object at rest will stay at rest, and an object in motion will continue to move at a constant speed and direction unless acted upon by an external force.

Motion draws our attention. Motion itself can be beautiful, causing us to marvel at the forces needed to create spectacular sights, such as that of a dolphin jumping out of the water, the flight of a bird, or the orbit of a satellite. The study of motion is kinematics, but kinematics only describes the way objects move—their velocity and acceleration. Dynamics considers the forces that affect the motion of moving objects and systems. Newton's laws of motion are the foundation of dynamics. These...