Tiêu đề 6. (KINEMATICS W.S-1 TO 4)_VOL-1(153 TO 206).pdf ✅

VIII – Physics (Vol – I) Olympiad Class Work Book Kinematics Relative motion Rain umbrella Point of projection Equation of projectory Angle of projection The time of descent Maximum height Range Time of flight Velocity of projetile Horizontal range Horizontal projection from the top of the tower When a particle is thrown obliquely from the earth suface Aircraft wind River boat Graph Projectile motion CONCEPT FLOW CHART
Olympiad Class Work Book VIII – Physics (Vol – I) KINEMATICS Galileo Galilei Galileo Galilei (1564-1642) – Italian astronomer, scientist and philosopher, who played a leading role in the Scientific Revolution. Galileo improved the telescope and made many significant discoveries in astronomy. His findings encouraged him to speak out for the Copernican view that the earth re volved around the sun. However, his views were considered heretical, and he was placed under house arrest. His greatest scientific works included Two New Sciences about kinetics and the strength of materials.
VIII – Physics (Vol – I) Olympiad Class Work Book KINEMATICS Introduction: The study of motion of bodies not considering the cause of motion is called Kinematics. Recap of previous class synopsis. Equations of Motion: When particle moves with zero acceleration: a) It is unidirectional motion with constant speed b) Magnitude of displacement is always equal to the distance travelled c) v=u , s=ut [ as a=0] When particle moves with non zero acceleration: a) acceleration is said to be constant when both the magnitude and direction of acceleration remains constant. b) Equation of motion in scalar form Equation of motion in vector form v u at        v u at   1 2 s ut at 2      1 2 s ut at 2   2 2 v u 2as       2 2 v u 2as         u v s t 2            u v s t 2 n    a s u (2n 1) 2       n a s u (2n 1) 2 Motion in One Dimension: In One-Dimension, the position of a particle is completely described by using one co-ordinate only. In 1D motion initial velocity and acceleration are parallel or anti parallel to each other. MOTION UNDER GRAVITY: The uniform acceleration of a free falling body towards the centre of the earth due to earth’s gravitational force is called acceleration due to gravity. It is denoted by ‘g’. Its direction is always towards to the centre of the earth.
Olympiad Class Work Book VIII – Physics (Vol – I) The average value of g on the earth surface is 9.8ms-2 or 980cms-2 and that of the moon is 1.63ms-2 (gearth/6). i) Free Fall Body: Motion of all bodies falling towards the earth when air resis- tance is ignored is known as free fall. For free fall, u = 0, a = +g and s = h a) v gt  b) 1 2 2 h gt  c) 2 v gh  2 d)   1 2 1 2 n h g n   ii) Projected Vertically Upward: For a body projected vertically upwards, u  0 , a = -g(since velocity and acceleration vectors are opposite) Maximum height : The vertical distance travelled by a body before its velocity becomes zero is called maximum height reached by the body. we know that, 2 2 v u 2as   here, a =-g, s = h, V=0  2 2 0 u 2gh     2 u 2gh   2 u h 2g  . Time of ascent : Time taken by the body to reach the highest point is called time of ascent ( a t ). Here a =-g, t = t a , V=0, ; v u gt o u gt     a a  a u t g  Time of descent : Time taken by the body to travel from the maximum height to the ground is called time of descent ( td ). here, u=0, a =+g, t = td , V=0+gtd  d u t g  . In the absence of air resistance, time of ascent is equal to time of descent. Time of flight: The total time spent by the body in air is called time of flight (t) is given by      a d u u 2u t t t g g g Velocity on reaching the ground: When a body is dropped from a height h, its initial velocity is zero. Let the final velocity on reaching the ground be v. For a freely falling body, v2 – u2 = 2gh, but u = 0 therefore, 2 2 2 v 0 2gh v 2gh v 2gh      