{"id":17437,"date":"2017-11-01T11:14:04","date_gmt":"2017-11-01T11:14:04","guid":{"rendered":"https:\/\/cbselibrary.com\/?p=17437"},"modified":"2017-11-01T11:14:04","modified_gmt":"2017-11-01T11:14:04","slug":"frank-icse-solutions-for-class-9-physics-chapter-3-laws-of-motion-solutions","status":"publish","type":"post","link":"https:\/\/cbselibrary.com\/frank-icse-solutions-for-class-9-physics-chapter-3-laws-of-motion-solutions\/","title":{"rendered":"Frank ICSE Solutions for Class 9 Physics Chapter 3 – Laws of Motion Solutions"},"content":{"rendered":"
Frank ICSE Solutions for Class 9 Physics Chapter 3 – Laws of Motion Solutions<\/p>\n
PAGE NO: 113. Solution – 02.<\/p>\n A book lying on a table will remain placed at table unless it is displaced by some external force. This is an example of inertia of rest. Solution – 03.<\/p>\n The greater is the MASS , the greater is the inertia of the object.<\/p>\n Solution – 04.<\/p>\n An object possess two kind of inertia, inertia of rest and inertia of motion.A book lying on a table will remain placed at table unless it is displaced by some external force. This is an example of inertia of rest. Solution – 05.<\/p>\n 1 Newton is the force which when applied to a body of unit mass produces a unit acceleration in it. 1 newton would produce acceleration of 1 ms-2 in a mass of 1 kg.<\/p>\n Solution – 06.<\/p>\n The acceleration produced bya force in an object is directly proportional to the applied FORCE and inversely proportional to the MASS of the object.<\/p>\n Solution – 07.<\/p>\n SI unit of force is Newton (N).<\/p>\n Solution – 08.<\/p>\n Acceleration is the physical quantity associated with N kg-1.<\/p>\n Solution – 09.<\/p>\n 1 N = 105 Dyne.<\/p>\n Solution – 10.<\/p>\n As mass of loaded van is greater than sports car so it would require more force to stop.<\/p>\n Solution – 11.<\/p>\n We know force = mass X acceleration. Solution – 12.<\/p>\n SI unit of force is Newton whereas CGS unit of force is dyne. Solution – 13.<\/p>\n SI unit of momentum is kgms-1.<\/p>\n Solution – 14.<\/p>\n Momentum is defined as the amount of motion contained in the body. It is given by the product of the mass of the body and its velocity.<\/p>\n Solution – 15.<\/p>\n Momentum is the physical quantity associated with the motion of the body.<\/p>\n Solution – 16.<\/p>\n Momentum is possessed by bodies in MOTION.<\/p>\n Solution – 17.<\/p>\n A fast pitched soft ball has more momentum.<\/p>\n Solution – 18.<\/p>\n SI unit of momentum is kgms-1 and CGS unit of momentum is g cms-1. Solution – 19.<\/p>\n A body at rest has zero momentum as its velocity is zero.<\/p>\n Solution – 20.<\/p>\n According to Newton’s third law, for every action there is always an equal and opposite reaction.<\/p>\n Solution – 21<\/p>\n When a force acts on a body then this is called an action.<\/p>\n Solution – 22.<\/p>\n No, action and reaction never act on a same body they always act simultaneously on two different bodies.<\/p>\n Solution – 23.<\/p>\n 2nd law of motion gives the definition of force.<\/p>\n Solution – 24.<\/p>\n Newton’s third law explains this statement.<\/p>\n Solution – 25.<\/p>\n Force is a vector quantity.<\/p>\n Solution – 26.<\/p>\n This means these forces are balanced forces.<\/p>\n Solution – 27.<\/p>\n Passengers tend to fall sideways when the bus takes a sharp turn due to the inertiaof direction.<\/p>\n Solution – 28.<\/p>\n Passengers are thrown in the forward direction as the running bus stops suddenly because due to their inertia of motion, their upper body continues to be in the state of motion even though the lowerbody comes to rest when the bus stops<\/p>\n Solution – 29.<\/p>\n Passengers tends to fall in backward direction when bus starts suddenly because due to their inertia of rest, as soon as the bus starts, their lower body comes in motion but the upper body continues to be in the state of rest. <\/p>\n Solution – 30.<\/p>\n No, internal forces cannot change the velocity of a body.<\/p>\n Solution – 31.<\/p>\n When a hanging carpet is beaten using a stick, the dust particles will start coming out of the carpet because the part of the carpet where the stick strikes, immediately comes in motion while the dust particle sticking to the carpet remains at rest . Hence a part of the carpet moves ahead alongwith the stick, and the dust particles fall down due to the earth’s pull.<\/p>\n Solution – 32.<\/p>\n When we shake the branches of a tree, the fruits and leaves remain in state of rest while branches comes in rest so fruits and leaves are detached from the tree.<\/p>\n Solution – 33.<\/p>\n We know force = mass X acceleration Solution – 34. PAGE NO: 114. initial velocity of the object = 0 ms-1 Solution – 36.<\/p>\n Initial velocity of the truck = 0 ms-1 Solution – 37.<\/p>\n Momentum is used for quantifying the motion of body.<\/p>\n Solution – 38.<\/p>\n When we fire a gun, a force is exerted in the forward in the forward direction as the bullets comes out; in reaction to which an equal and opposite force is act in the backward direction and hence, we feel a backward jerk on the shoulder.<\/p>\n Solution – 39.<\/p>\n A person applies force on water in backward direction and water according to third law of motion water apply an equal and opposite force in forward direction which helps a person to swim.<\/p>\n Solution – 40.<\/p>\n Newton’s third law of motion is involved in the working of a jet plane.<\/p>\n Solution – 41.<\/p>\n Yes, a rocket can propel itself in a vacuum once it is given initial velocity.<\/p>\n Solution – 42.<\/p>\n Action is equal and opposite to reaction but they act on different bodies and object moves as movement requires an unbalanced force and these are provided once inertia is overcome.<\/p>\n PAGE NO: 125. Sir Isaac Newton stated the law of gravitation.<\/p>\n Solution – 02.<\/p>\n Every object in the universe attracts every other object with a force directly proportional to the product of their masses and inversely proportional to the square of distance between them.<\/p>\n Solution – 03.<\/p>\n Gravity is the force of attraction between the object and the earth whereas gravitation refers to the force of attraction that exists between any two bodies that possess mass.<\/p>\n Solution – 04.<\/p>\n Acceleration due to gravity is the acceleration experienced by a body during free fall.<\/p>\n Solution – 05.<\/p>\n g = GM\/R2<\/p>\n Solution – 06.<\/p>\n We know that law of gravitation. Solution – 07.<\/p>\n SI unit of constant of gravitation is Nm2kg-2.<\/p>\n Solution – 08.<\/p>\n we know that law of gravitation. Solution – 09.<\/p>\n All objects in the universe attract each other along the line joining their CENTRES.<\/p>\n Solution – 10.<\/p>\n The force of attraction between any two material objects is called FORCE OF GRAVITATION.<\/p>\n Solution – 11.<\/p>\n The gravitational force of the earth is called earth’s GRAVITY.<\/p>\n Solution – 12.<\/p>\n The Gravity is a particular case of GRAVITATIONAL FORCE OF EARTH.<\/p>\n Solution – 13.<\/p>\n The value of G is extremely SMALL.<\/p>\n Solution – 14.<\/p>\n Yes the law of gravitation is also applicable in case of the sun and moon.<\/p>\n Solution – 15.<\/p>\n we know that law of gravitation. Solution – 16.<\/p>\n Objects fall towards the earth due to force of gravitation.<\/p>\n Solution – 17.<\/p>\n Because the masses of persons are not large enough to overcome the value of small constant of gravitation so the force of gravitation is very small and negligible to feel.<\/p>\n Solution – 18.<\/p>\n Initial speed of ball is = 4.9 ms-1. Solution – 19.<\/p>\n g = GM\/R2.<\/p>\n Solution – 20.<\/p>\n Value of the g at the surface of the earth is 9.8ms-2<\/p>\n Solution – 21.<\/p>\n Mass of the body is constant at all positions so mass will not change. But weight will change as gravity on the surface of earth is almost 6 times than on the surface of the moon, so its weight will increase almost 6 times on the surface of earth.<\/p>\n Solution – 22.<\/p>\n We will weigh more on the surface of the earth.<\/p>\n Solution – 23.<\/p>\n Beam balance is used to measure the mass of a body.<\/p>\n Solution – 24.<\/p>\n Spring scale is used to measure the weight of a body.<\/p>\n Solution – 25.<\/p>\n The weight is greater at the poles than the equator.<\/p>\n Solution – 26.<\/p>\n Newton 1N = 9.8 kgwt.<\/p>\n Solution – 27.<\/p>\n We will weigh more on earth surface as value of g is greater on earth surface.<\/p>\n Solution – 28.<\/p>\n No, the force of gravitation between two objects does not depend on the medium between them.<\/p>\n Solution – 29.<\/p>\n we know that law of gravitation. PAGE NO: 126. Yes, in absence of gravity all freely falling body have same force acting on them.<\/p>\n Solution – 31.<\/p>\n g= GM\/R2 Solution – 32.<\/p>\n Yes a body falling freely near the earth surface has a constant acceleration.<\/p>\n Solution – 33.<\/p>\n As we know Solution – 34. PAGE NO: 128. Force is that external agency which tends to change the state of rest or the state of motion of a body.<\/p>\n Solution – 02.<\/p>\n 1 Newton is the force which when applied to a body of unit mass produces a unit acceleration in it.<\/p>\n Solution – 03.<\/p>\n Newton is the SI unit of force whereas dyne is the CGS unit of force. Solution – 04.<\/p>\n No, force is a vector quantity.<\/p>\n Solution – 05.<\/p>\n
\nSolution – 01.
\nThe property by which a body neither changes its present state of rest or of uniform motion in a straight line nor tends to change the present state,is known as inertia.<\/p>\n
\nA ball rolling on the ground will continue to roll unless the external force , the force of friction between the ball and the ground stops it.<\/p>\n
\nA ball rolling on the ground will continue to roll unless the external force , the force of friction between the ball and the ground stops it.<\/p>\n
\na= f\/m = 12 N \/ 4 kg. = 3 ms-2
\nso acceleration of the body would be 3 ms-2.<\/p>\n
\n1 newton \/ 1dyne = 105.<\/p>\n
\nAnd their ratio is = 1000 X 100 g ms-1= 1:10.<\/p>\n
\nF1 = 10 X 5 = 50 dyne.
\nF2 = 20 X 2 = 40 dyne.
\nSo first body require more force<\/p>\n
\n<\/p>\n
\nSolution – 35.<\/p>\n
\nAcceleration of the object = 8 ms-2.
\nTime = 5 s.
\nDistance covered would be S = ut + 1\/2 at2.
\nS = 1\/2 X 8 X 5 X5 = 100 m.<\/p>\n
\nDistance covered by truck = 100 m
\nTime taken to cover this distance = 10 s.
\nWe know Distance covered would be S = ut + 1\/2 at2.
\n100 =1\/2 Xa X100
\na= 2 ms-2.
\nMass of truck = 5 metric tons = 5000 kg.
\nForce acted on truck = mass X acceleration
\nForce = 5000 X 2 = 10000 N.<\/p>\n
\nSolution – 01.<\/p>\n
\nF = G ( m1 X m2)\/R2.
\nHere G is universal constant and is called constant of gravitation. It doesnot depend upon on the value of m1,m2 or R.
\nIts value is same between any two objects in the universe. <\/p>\n
\nF = G ( m1 X m2)\/R2.
\n(a) If distance between them is halved then put R = R\/2.
\nF = 4 X G( m1 X m2)\/ R2.
\nF1 = 4 F.
\n(b) If distance between them is doubled then put R = 2R.
\nF = G( m1 X m2)\/ 4R2.
\nF1 = F\/4.
\n(c) If distance between them is made four times then put R = 4R.
\nF = G( m1 X m2)\/16 R2.
\nF1 = F\/16.
\n(d) If distance between them is infinite then put R = infinite.
\nF = G( m1 X m2)\/ R2.
\nF1 = 0.
\n(e) If distance between them is almost zero then put R = 0.
\nF = G( m1 X m2)\/ 0.
\nF1 = infinite.<\/p>\n
\nF = G ( m1Xm2)\/R2.
\nMass of earth = 6X1024kg.
\nMass of the person = 100 kg.
\nG = 6.7 X10-11 Nm2kg-2.
\nRadius of earth = 6.4 X 1014.
\nF = (6.7 X10-11X 100 X 6 X1014 )\/ (6.4 X6.4 X1012) = 981.4N
\nForce of gravity due to earth acting on a 100 kg person is 981.4 N.<\/p>\n
\nAcceleration due to gravity = -9.8 ms-2.
\n(a) We know v2 – u2 =2as
\nAt highest point final velocity is zero so
\n0 – 4.9 X 4.9 = 2 X (-9.8) S
\nS = 1.125 m
\n(b) We know v = u + at
\n0 = 4.9 – 9.8 t
\nT = 0.5 sec.
\n(c) for highest point initial velocity is zero
\nAcceleration due to gravity is = 9.8 ms-2.
\nFinal velocity at ground is v
\nV2 – 0 = 2 X9.8 X 1.125
\nV = 4.9 ms-1.
\nTime taken to reach ground from highest point
\nV = u + at
\n4.9 = 0 + 9.8 t
\nT = 4.9\/9.8 = 0.5 sec.
\nSo time of ascent is equal to time descent.<\/p>\n
\nF = G ( m1Xm2)\/R2.
\nNow m1 = 2 m1
\nm2 = 2 m2
\nR = 2 R
\nF1 = G ( 2m1 X2 m2)\/4R2.
\nF1 = F
\nSo force between them remains same.<\/p>\n
\nSolution – 30.<\/p>\n
\nit means acceleration due to gravity is directly proportional to the mass of body and inversely proportional to the square of distance between earth and object.<\/p>\n
\ng= 1\/R2
\nso value of g is more at poles than equator so value of g is maximum near a camp site in Antarctica as this lie on the pole.<\/p>\n
\n<\/p>\n
\nSolution – 01.<\/p>\n
\n1 N = 105 dyne.<\/p>\n