1.4 Physics and Defense Technology

• The modern defense force has different branches like air force , army , navy and space force.
• All of these defense forces demand different knowledge and advancement of physics like:

• Modern electronics 

• Sensing systems

• Nuclear physics

• Laser guidance and satellite technology,

• high-energy-density physics

• Hydrodynamics

• As the name implies, radars use radio waves to determine the distance and velocity of the targets they hit. A radar system usually consists of a transmitter to send out radio signals and a receiver to catch any reflected energy from targets.

• The word RADAR is an acronym derived from the phrase Radio Detection And Ranging. 
• It applies to electronic equipment designed for detecting and tracking the presence of objects like ships, vehicles, aircraft, missiles, etc which are at certain distances from the location of the radar. 
• Radar can also be utilized in civilian applications particularly in:

• A missile is a rocket-propelled or jet-propelled weapon designed to deliver an explosive weapon with great accuracy at high speed.
• Jets get the oxygen to burn fuel from the air while rockets carry their own oxygen. 
• Missiles are different types. The well-known ones are cruise missile and ballistic missile. 

• Cruise missiles are jet-propelled throughout their flights. 

• Ballistic missiles are rocket-powered only in the initial phase of flight, It is governed by Newtonian mechanics.

Infrared wave detection for night vision

• It is detected by infrared detecting devices.
• Infrared (IR) devices will typically use heat emissions to identify objects that cannot be detected using available light sources. 
• Infrared vision is used extensively by the military for various purposes like night vision, navigation, hunting, hidden-object detection and targeting.