Physics of Balloons and Submarines

This lecture briefly describe on Physics of Balloons and Submarines. Helium, Hydrogen and hot-air are used in balloons and submarines have mass. Submarines navigate through the ocean using sound waves. This method know as SONAR, uses the Doppler Effect to calculate the distance, direction and speed of another object. here briefly focus on Why don’t they fall down and What is the force that makes them go up.