These are\u00a0NCERT book Solutions class-9 Gravitation (In Text Questions) . Questions in this page are those questions that occur in between the texts at the end of each concept.and I have given the page number so you can find them easily in your book.<\/p>\n
I have also been writing the notes for this chapter to learn more about notes you can follow this<\/p>\n
[standout-css3-button href=”https:\/\/physicscatalyst.com\/Class9\/gravitation.php#1″]Class 9 gravitation notes[\/standout-css3-button]<\/p>\n
If you want to get the solutions of first 11 questions follow this link
\n[standout-css3-button href=”https:\/\/physicscatalyst.com\/article\/ncert-book-solutions-class-9-gravitation-part-1\/”]gravitation solutions part 1[\/standout-css3-button]<\/p>\n
For rest of the NCERT book Solutions class-9 Gravitation (Part 2) please visit this link Every body in universe attracts every other body with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between them. The force acts along the line joining the two bodies.<\/p><\/blockquote>\n Force $F$ be the force of attraction between two objects $P$ and $Q$ of masses $M$ and $m$ is given by Question 2<\/strong><\/span> Page 136<\/span><\/span><\/strong> Question 2<\/span><\/strong> Page 138<\/span><\/span><\/strong> Question 2<\/span><\/strong> Page 141<\/span><\/span><\/strong> Answer<\/span><\/strong><\/p>\n It is difficult to hold a school bag having a thin strap because the pressure on the shoulders is quite large. This is because the pressure is inversely proportional to the surface area on which the force acts. The smaller is the surface area the larger wold be the pressure on the surface. In the case of a thin strap, the contact surface area is very small. Hence pressure exerted on the shoulder is very large.<\/p>\n Question 2<\/span><\/strong> Question 3<\/span><\/strong> Page 142<\/span><\/span><\/strong><\/p>\n Question 1<\/span><\/strong> Question 2<\/span><\/strong> [standout-css3-button href=”https:\/\/physicscatalyst.com\/class9.php”]Class 9 science study material[\/standout-css3-button] [standout-css3-button href=”https:\/\/physicscatalyst.com\/class9_maths.php”]Class 9 maths study material[\/standout-css3-button] [standout-css3-button href=”https:\/\/physicscatalyst.com\/download9.php”]Class 9 downloads[\/standout-css3-button]<\/p>\n","protected":false},"excerpt":{"rendered":" These are NCERT solutions for class-9 chapter named Gravitation. Questions in this page are those questions that occur in between the texts at the end of each concept.and I have given the page number so you can find them easily in your book.
\n[standout-css3-button href=”https:\/\/physicscatalyst.com\/article\/ncert-book-solutions-class-9-gravitation-part-2\/”]gravitation solutions part 2[\/standout-css3-button]
\nPage 134<\/span><\/span><\/strong>
\nQuestion 1<\/span><\/strong>
\nState the Universal law gravitation?
\nAnswer<\/strong><\/span>
\nAccording to Universal Law of Gravitation every object in universe attracts every other object with a force known as Gravitational force.
\nIt states that<\/p>\n
\n$F = G\\frac{{Mm}}{{{r^2}}}$
\nHere G is the constant known as Universal Gravitational constant and its value is $G = 6.673 \\times {10^{ – 11}}N{m^2}K{g^{ – 2}}$<\/p>\n
\nWrite the formula to find the\u00a0magnitude of the gravitational\u00a0force between the earth and an\u00a0object on the surface of the earth.
\nAnswer<\/strong><\/span>
\nLet $F$ be the be the force of attraction between earth and an object on its surface. Again assume that $M_{e}$ be the mass of earth and $m$ be the mass of object on the surface of earth. Formula for the\u00a0magnitude of the gravitational\u00a0force between the earth and an\u00a0object on the surface of the earth is given by using Universal Law of Gravitation. So required formula is
\n$F = G\\frac{{Mm}}{{{r^2}}}$<\/p>\n
\nQuestion 1<\/span><\/strong>
\nWhat do you mean by free fall?
\nAnswer<\/span><\/strong>
\nGravity of earth attracts every object towards its center. When an object is dropped from a certain height , it begins to fall towards Earth’s surface under the influence of gravitational force. Such a motion of object is called free fall.<\/p>\n
\nWhat do you mean by acceleration due to gravity?
\nAnswer<\/span><\/strong>
\nWhen an object falls freely towards the surface of earth from a certain height, then its velocity changes. This change in velocity produces acceleration in the object which is known as acceleration due to gravity denoted bu letter $g$. The value of acceleration due to gravity is $g=9.8m\/s^{2}$ .<\/p>\n
\nQuestion 1<\/span><\/strong>
\nwhat are the differences between mass of an object and its weight?
\nAnswer.<\/span><\/strong>
\nMass:-
\n1. Mass is the quantity of matter contained in the body
\n2. It is the measure of inertia of the body
\n3. It is a constant quantity for any object.
\n4. It is a scalar quantity and only only has magnitude
\n5. SI unit of mass is Kg
\nWeight:-
\n1. Weigh is the gravitational force acting on the body
\n2. It is the measure of gravity
\n3. Weight of an object is not a constant quantity it is different at different laces.
\n4. It is a vector quantity as it has both magnitude and direction.
\n5. Its SI unit is N (newton) same as the SI unit of force.<\/p>\n
\nWhy is the weight of an object on the moon (1\/6)th its weight on the earth?
\nAnswer<\/span><\/strong>
\nGravity is directly related to mass. The more mass an object has, the more gravitational pull it has.
\nNow,\u00a0\u00a0the moon is significantly smaller than the earth (in fact, it is about the size of the earth’s core).\u00a0Gravity is dependent on the size of the object. Your weight on the moon is 1\/6 of that on earth because the moon has 1\/6 the mass of the earth.<\/p>\n
\nQuestion 1<\/span><\/strong>
\nWhy is it difficult to hold a school bag having a strap made of a thin and strong string?<\/p>\n
\nWhat do you mean by buoyancy?
\nAnswer<\/span><\/strong>
\nThe upward force exerted by a liquid on an object that is immersed in it is known as buoyancy.<\/p>\n
\nWhy does an object float or sink when placed on the surface of water?
\nAnswer<\/span><\/strong>
\nIf the density of an object is more then the density of the liquid then the object would sink this happens because in this case buoyant force that is acting on the object due to liquid is less than the force of gravity acting on the object. If the density of object is less than the density of the liquid , then it floats on the surface of the liquid , this happens because the buoyant force acting on the object is greater than the force of gravity.<\/p>\n
\nYou find your mass to be 42 Kg on a weighting machine. Is your more or less than 42 K?
\nAnswer<\/span><\/strong>
\nOn a weighing machine mass is measured by comparing the weights. So when you weigh your body an upward force (buoyant force) acts on it which causes machine to show\u00a0your\u00a0weight less than the actual weight.<\/p>\n
\nYou have a bag of cotton and an iron bar, each indicating a mass of 100 Kg when measured on a weighing machine. In reality one is heavier than other. Can you say which one is heavier and why?
\nAnswer<\/span><\/strong>
\nActual weight of any object is equal to the sum of its measured weight and the buoyant force.\u00a0The bag of cotton is heavier since\u00a0it is larger\u00a0than iron bar, so \u00a0the buoyant force\u00a0is larger in case of cotton henceactual weight of cotton bag is more and it is heavier<\/p>\nIf you are interested in other links containing class 9 notes in science and maths along with free download links consider following the links given below<\/span><\/em><\/span><\/h4>\n
\nPage 134
\nQuestion 1
\nState the Universal law gravitation?
\nAnswer
\nAccording to Universal Law of Gravitation every object in universe attracts every other object with a force known as Gravitational force.
\nIt states that<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[24,279],"tags":[],"class_list":["post-2430","post","type-post","status-publish","format-standard","hentry","category-general","category-ncert-solutions"],"yoast_head":"\n