Why are rockets streamlined

This source of drag depends on the shape of the rocket and is called form drag. As air flows around a body, the local velocity and pressure are changed. Since pressure is a measure of the momentum of the gas molecules and a change in momentum produces a force , a varying pressure distribution will produce a force on the body. We can determine the magnitude of the force by integrating, or adding up the local pressure times the surface area around the entire body.

The base area of a model rocket produces form drag. Accurately determining the size of the drag force is very difficult in practice.

The size of the drag changes depending on the thrust setting and the flow of gases at the base of the rocket. When the engine is operating, the drag is usually low. But when the engine is off during the coast phase of a model rocket, the entire base of the rocket produces a large drag.

The centre of mass can be moved closer to the nose cone end of a rocket by adding some mass near the nose cone. This will increase stability. The single point at which all of the aerodynamic forces are concentrated is called the centre of pressure. To find the approximate position of the centre of pressure, draw an outline of the rocket on a piece of paper. The centre of the area of the outline shape is approximately the centre of pressure. For a rocket to be stable, the centre of pressure needs to be closer to the tail end than the centre of mass.

If the centre of pressure is at the same position as the centre of mass, the rocket will tumble. Stability increases as the distance between the centre of mass and the centre of pressure increases. Placing fins at the tail end of a rocket moves the centre of pressure closer towards the tail end and increases stability. Can you think of any reasons for the difference in diagnoses? In human females, each time during maturation and release of egg the inner wall of uterus thickens.

Name the hormone which would be released during the following situations:. Given below are certain food items required for proper nourishment of adolescents. Name the nutrients present in the food items and write their functi. In Fig. Given below are a few of those changes. We can use Bernoulli's equation to relate the pressure and velocity along the streamline.

Since no mass passes through the surface of the airfoil or cylinder , the surface of the object is a streamline. Airplanes fly by moving through almost still air, yet we design and test them using wind tunnels, where the airplane model is fixed and the air is made to move past the model.

This idea of keeping the airfoil fixed and having the air stream past the airfoil can be a bit confusing. Yet you experience the same kind of thing every day!