#### Kerala PSC General Science Book Study Materials Page 13

Book's First PageEscape Velocity The escape velocity at a given height is 2 times the speed in a circular orbit at It is the speed at which the kinetic energy the same height. plus the gravitational potential energy of an object is zero. Kepler"s Laws For a spherically symmetric body, the escape velocity at a given distance is Johannes Kepler developed three laws which calculated by the formula described the motion of the planets across the 2GM ve sky. r Where G is the universal gravitational 1. Law of Orbits: It state that all planets constant (G = 6.67×10−11 m3 kg−1 s−2), M move in elliptical orbits, with the sun at the mass of the planet, star or other body, and r the distance from the center of one focus. gravity. 2. Law of Areas: It states that a line that connects a planet to the sun sweeps out n escape 11.2 km/ s equal areas in equal times. 3. Law of Periods: It states that the square of 1 GMm m n2 the period of any planet is proportional to Earth 2 r 2GM the cube of the semi major axis of its orbit. n escape r P2 a3 The Escape velocity on the earth’s surface Kepler"s laws were derived for orbits around is 11.2 km/s and on the moon’s surface 2.4 the sun, but they apply to satellite orbits as km/s. well. GENERAL PROPERTIES OF MATTER Matter is a substance that has inertia and occupies physical space. Elasticity It is the property of a material whose Stress (σ) dimensions can be changed by applying a force to it (for example, pushing, pulling, The stress applied to a material is the force twisting, or compressing), but per unit area applied to the material. Force F subsequently returns to its original shape. Stress () Area A The deforming force is called a stress, and Where, Stress = stress measured in Nm-2 the deformation is called the strain. or pascals (Pa) Plasticity F = force in newtons (N) A = cross-sectional area in m2 It is the deformation of a (solid) material undergoing non-reversible changes of Strain (ε) shape in response to applied forces. Plastic deformation is observed in most It is the relative change in the shape or materials including metals, soils, rocks, size of an object due to externally-applied concrete, foams, bone and skin. forces. Extension L Strain () Lenght L 12

GET IN TOUCH WITH US

Kerala PSC Blog, Karimbam P O, Kannur, Kerala 670142

OTHER INITIATIVES

© Copyright Monsoon Malabar All Rights Reserved • Privacy • Powered by monsoonmalabar.com