For an object, the state of rest is considered to be the state ofzerospeed. According to Newton's First Law of Motion which states that a body at rest will remain at rest unless an external force acts on it, and a body in motion at a constant velocity will remain inmotion in a straight line unless acted upon by an externalforce.

Distance-time graph determines its speed. It shows us how the distance changes with respect to time. When the object moving with a constant speed, the distance-time graph for the motion of an object is straight line graph.

• Convex and concave mirrors are example of the spherical mirror.
• If the spherical mirror’s inside surface is reflective than it is a concave mirror and if the outside’s surface is reflective than it is convex mirror.
• Concave mirror are converging mirror and mostly used by dentist and in the headlight of the car whereas convex mirror are diverging mirror in which image is formed small and virtual images and mainly used as side mirror in vehicles.
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Make the surfaces smoother, Reduce the forces acting on the surfaces, and Reduce the contact between the surfaces are used to reduce friction. Friction is a catchall word that refers to any force that resists relative tangential motion (or intended motion). "Relative tangential motion" is a fancy way to say "slipping" or "sliding". Its direction is opposite the relative velocity (or intended velocity).

Surface tension is the elastic tendency of a fluid which makes it acquire the least surface area possible. Surface tension allows insects usually to float on a water surface.

•  Kaveri Known to devout Hindus as Ganges of the South.
• The Kaveri River is celebrated for its scenery and sanctity in Tamil literature, and its entire course is considered holy ground.
• The river is also important for its irrigation canal projects.

The Panama Canal connects the Atlantic Ocean with the PacificOcean.

• The canal permits shippers of commercial goods, ranging from automobiles to grain, to save time and money by transporting cargo more quickly between the Atlantic and Pacific Oceans.

• San Francisco hosted the 1915 Panama-Pacific International Exposition, which celebrated the opening of the Panama Canal.

Siachin glacier is between India and Pakistan. It’s located in the northern state of Jammu and Kashmir. And was militarized under operation meghdoot, for preventing it to be taken over by Pakistan in 1984.

• The Kalahari Desert is a large semi-arid sandy savanna in Southern Africa extending for 900,000 square kilometres (350,000 sq mi), covering almost Botswana, some parts of Namibia and regions of South Africa.
• The word “Kalahari” is derived from the Tswana word Kgala, which meant "the great thirst", or Kgalagadi, which means "a waterless place". It has vast areas covered by red sand without any permanent surface water.
• It is a sand-covered plain, which everywhere is 3,000 feet (900 metres) or more above sea level. Surface water is nearly almost zero because all of the rain that falls disappears immediately into the deep sand.
• Reddish colored soil is found in this dessert which is low in organic material. The northern Kalahari do not have the appearance of a desert at all. It has open woodlands, palm trees growing among thorn brush, and forests of both evergreen and deciduous trees.

The Equator is the line lies at 0 ° latitude and divides the Earth into two equal hemispheres- northern and southern hemispheres). The Equator is about 40,075 kilometers (24,901 mi) long, of which 78.7% lies across water and 21.3% over land. Indonesia is the country got the longest equatorial line lay across the water and land.