## describing motion class 9

→ Acceleration is seen in non-uniform motion and it can be defined as the rate of change of velocity with time. For a moving body it is never zero. (ii) Motion of a ball dropped from the roof of a building. All these objects are in motion. Motion Class 9 Science Chapter Introduction You all use common things around you that are moving like if you see around you, observe air moving around you, like you have clocks with the hands moving, you all know that day and night is caused because of motion of … of Describing Motion and Related Concepts Class 9 Notes | EduRev for Class 9, the answers and examples explain the meaning of chapter in the best manner. Distance can be equal to or greater than displacement, Displacement can be equal to or less than. Ex. (ii) The distance travelled by … this is your one stop solution. An object may seem to be moving to one observer and stationary to another. When a body covers unequal distances in equal intervals of time, the body is said to be moving with a nonuniform motion. Negative Acceleration: If the velocity of an object decreases with time, then the acceleration of the object is known as negative acceleration. May 19, 2015. Memorize: When a body moves with constant velocity, the average velocity is equal to instantaneous velocity. (i)    Distance travelled by the train = 50 + 100 + 200 + 400 = 750 km. how_to_reg Follow . In other words, the movement of an object is known as the motion of the object. It is the shortest distance between two points between which the body moves. To Study Describing Motion and Related Concepts Class 9 Notes | EduRev for Class 9 → For non-uniform motion in a given line, average velocity will be alculated in the same way as done in average speed. EduRev is like a wikipedia Units In SI system: metre (m) In CGS system : centimetre (cm). → Deaceleration is seen in non-uniform motion during decrease in velocity with time. When a body covers unequal displacement in equal intervals of time, the body is said to be moving with variable velocity. (i) The body must cover equal displacement in equal intervals of time. Velocity H The velocity of a body is the displacement of a body per unit time. Download NCERT Chapters and Books in pdf format. (ii) Motion of a ball rolling down an inclined plane. STATICS: Statics deals with bodies at rest under the effect of different forces.DYNAMICS: Dynamics deals with the bodies in motion. thumb_up Like (8) visibility Views (41.9K) edit Answer . To describe the motion of an object, we can different graphs. Class 9 Describing Motion and Related Concepts Class 9 Notes | EduRev Summary and Exercise are very important for Define retardation. Do check out the sample questions Final velocity = Initial velocity + Acceleration × Time. (ii) It should cover equal distances in equal intervals of time but its direction must change. Oct 18, 2020 - Describing Motion and Related Concepts Class 9 Notes | EduRev is made by best teachers of Class 9. (a) At rest. Sign of velocity represents the direction of motion of body. In order to master this chapter, you need to understand the theory behind the various concepts. (i) Acceleration. (ii) Motion of merry-go-round          (iii) Motion of a spinning top. If sign of velocity and acceleration are same it means speed of body will always increase. … Example 2: A car travelling with a speed of 20 km/hr comes into rest in 0.5 hrs. Fig: rotating Ferris wheel and different motions. Define retardation. Download NCERT Class 9 Science Motion NCERT Book and other CBSE KVS Science latest books free in pdf format chapter wise, NCERT Class 9 Science Motion. Positive or negative sign of acceleration always shows the direction of acceleration or direction of force but not represent direction of motion of body. The motion in animals is called LOCOMOTION. Ex. Motion is relative. MECHANICS:   Fig: mechanics and its branches The branch of physics which deals with the motion of non-living objects in everyday life is called mechanics or Classical mechanics. NCERT Exemplar Class 9 Science is very important resource for students preparing for IX Board Examination. person. where u = initial velocity, v = final velocity. From the given v-t graph, it can be inferred that the object is. Speed may or may not be equal to velocity. Average speed by an object (body) = 30 km/hr. The velocity of body decrease with time the motion is said to be retardation *the opposite of accelaration. just for education and the Describing Motion and Related Concepts Class 9 Notes | EduRev images and diagram are even better than Byjus! Ex. • Speed (v) = Distance Travelled/Time Taken = s/t. When a body covers equal distances in equal intervals of time however small may be time intervals, the body is said to describe a uniform motion.Example of uniform motion –, (i) An aeroplane flying at a speed of 600 km/h (ii) A train running at a speed of 120 km/h (iii) Light energy travelling at a speed of 3 × 108 m/s. Speed never decreases with time. Ex. Ex. Describing Motion and Related Concepts Class 9 Notes | EduRev chapter (including extra questions, long questions, short questions, mcq) can be found on EduRev, you can check out Class 9 lecture & lessons summary in the same course for Class 9 Syllabus. Velocity can decrease with time. (i) The motion of a bus leaving or entering the bus stop. Motion . These notes are prepared by the subject experts and are very useful for the effective … Member since Apr 1, 2017. Author of this … Practice these questions to … Suppose a body has initial velocity ‘u’ (i.e., velocity at time t = 0 sec.) (ii) Motion of a simple pendulum. (ii) Magnitude of the displacement in going from station A to station B = 400 km. but change in velocity = final velocity - initial velocity. The motion in animals is more apparent than the motion in plants. Thus, uniform circular motion is an accelerated motion. → If v > u, then ‘a’ will be positive (+ve). Types of Motion:(A) Linear motion:  A body has linear motion if it moves in a straight line or path. Copies of these textbooks may be downloaded and used as textbooks or for reference. → For non-uniform motion, average speed will describe one single value of speed throughout the motion of the body. Get the CBSE Class 9 Science notes for chapter 8 - Motion. (ii) The direction of motion of the body should not change. Ex. It is defined as the actual path traversed by a body. Very small objects like atoms and molecules and very large objects like planets, stars and galaxies are in motion.Thus, all objects ranging from the smallest atom to the largest galaxy are in continuous motion. • Acceleration (a) = Change in velocity/Time = (v-u)/t, where, v = final velocity, u = initial velocity. If we look around us, we find that there are number of objects which are in motion. for a moving body it is never zero. It is of two types:-(i) Statics and (ii) Dynamics. Equation of Motion (For Uniformly Accelerated Motion). (i) Motion of an electric fan. There are certain sections containing information about the movement of an object, acceleration, etc. You can also find Describing Motion and Related Concepts Class 9 Notes | EduRev ppt and other Class 9 slides as well. In order to solve these numerical problems with ease, students should have a clear understanding of these core sections. CBSE NCERT Solutions For Class 9 Science Chapter 8: Motion is an essential chapter in the Physics section of CBSE NCERT Science textbook for Class 9. Example of non-uniform motion – (i) An aeroplane running on a runway before taking off. (i) Motion of a moving car on a straight road. Ex. → If a body is travelling with non-uniform motion, then the speed will not remain uniform but have different values throughout the motion of such body. RD Sharma Solutions for Class 9 Mathematics, English Grammar (Communicative) Interact In English- Class 9, Class 9 Physics, Chemistry & Biology Tips & Tricks. → In such a motion the speed may be same throughout the motion but its velocity (which is tangential) is different at each and every point of its motion. Here we have provided NCERT Exemplar Problems Solutions along with NCERT Exemplar Problems Class 9.. MOTIONIf we look around us, we find that there are number of objects which are in motion. Calculate     (i)    the distance travelled by train and     (ii)    the magnitude of the displacement of the train on reaching station B. Sol.