What factors affect terminal velocity?

Terminal velocity is affected by factors such as the object's mass, its surface area, the fluid's density, and the drag coefficient.

Terminal velocity is a concept in physics that describes the maximum constant speed that a freely falling object eventually reaches when the resistance of the medium through which it is falling prevents further acceleration. This occurs when the force due to gravity is equal to the drag force acting on the object. Several factors can influence the terminal velocity of an object.

Firstly, the mass of the object plays a significant role. The greater the mass of the object, the greater the force of gravity acting upon it, and thus, the higher its terminal velocity. This is because a heavier object requires a larger drag force to balance out the gravitational force, which can only be achieved at higher speeds. Understanding Newton's First Law of Motion is essential in comprehending how an object in motion remains in motion at a constant velocity unless acted upon by an external force.

Secondly, the surface area of the object is also crucial. An object with a larger surface area experiences a greater drag force, which reduces its terminal velocity. This is why parachutes, which have a large surface area, are used to slow down the descent of people or objects.

The density of the fluid through which the object is falling is another important factor. If the fluid is denser, the drag force is larger, and the terminal velocity is lower. For example, an object will fall slower through water (a denser fluid) than through air. This is linked to the definition of temperature and its effect on fluid density, which in turn affects the drag force and terminal velocity.

Lastly, the drag coefficient, which depends on the shape of the object and the roughness of its surface, also affects the terminal velocity. A streamlined object, such as a skydiver in a head-first position, has a lower drag coefficient and thus a higher terminal velocity than a less streamlined object, like a skydiver with their limbs spread out. The concept of refraction can be used as an analogy to understand how different shapes and surfaces influence the path of motion, much like how light changes direction when it passes through different mediums.

IB Physics Tutor Summary: Terminal velocity is determined by the object's weight, shape, the thickness of the air or fluid it falls through, and how streamlined it is. Heavier and more streamlined objects fall faster, while larger and rougher ones fall slower. The speed also changes if the object is falling through something thick like water compared to air.