Newton's law of motion Questions and Answers

O out of 1 points A lady moves a suitcase of mass 22 3 kg with frictionless wheels across a horizontal floor by pulling on a cord attached to the suitcase making an angle of 8 45 5 degrees to the horizontal as shown in the diagram If the lady pulls the cord with a force of 55 2 N what distance will the suitcase have moved when she has been pulling for a time of 2 70 s in units of meters Selected Answer O 4 68

0 A ball released from the top of a tower travels of the 36 height of the tower in the last second of its journey The height of the tower is Take g 10 m s a 11 m b 36 m c 47 m d 180 m

times ius of Cically km hr 2 90 What force must man exert on rope to keep platform in equilibrium Take g 10 m s A 100N C300 N g Man 50 kg Platform 40 kg Figure 2 184 B 200 N D 500 N

ntact nt of ame 2 81 A boy standing on a weighing machine notices his weight as 400 N When he suddenly jumps upward the weight shown by the machine becomes 600 N The acceleration with which the boy jumps up is Take g 10 m s A 5 ms 2 B 3 4 ms 2 D 9 8 ms 2 C 6 ms 2

A string with a mass on each end hangs over a frictionless peg as shown The acceleration of the system has a magnitude of 1 0 kg 2 0 kg a 3 3 m s b 10 m s Oc 1 0 m s d 2 0 m s e 6 7 m s

Three blocks each of mass m are hanged vertically with the help of inextensible strings and ideal spring Initiall the system was in equilibrium At any instant lower most string is cut then acceleration of block B just after cutti the string is www c

A block of mass m is initially at rest on a rough incline of incline angle and attached to an initially relaxed nonlinear spring which exerts a restoring force of magnitude fres x kx ax Here is measured parallel to the incline from the block s initial position where the spring is relaxed The coefficient of kinetic friction is itself position dependent and is given by Hk x M Ho 1 x L e the the incline gets smoother as the block descends Leave g symbolically Find the block s speed as a function of a assuming that it does start moving down the incline and for the first phase of motion during which it is moving down the incline given that it starts from rest at x 0

c 4N d 6 N is 0 14 A block released from rest from the top of a smooth 20 The inclined plane of angle 8 reaches the bottom in time The same block released from rest from the top of another smooth inclined plane of angle 8 reaches the bottom in time t If the two inclined planes have the same height the relation between 21 Ap and t is 2 c 2sin 8 tsin 0 4 sin 8 sin 0 1 2 b d 12 1 4 t sin 0 t sin 0 pero a c sun fart near the a c

A thin circular ring of mass M and radius R is rotating about its axis with a constant angular velocity Four objects each of mass m are kept gently to the opposite ends of two perpendicular diameters of the ring The angular velocity of the ring will be 1 2 3 Ma M 4m M 4m M M 4m M 4m Mo

4 A box with mass m 1 25 kg is attached to a spring that is compressed a distance of 0 550 m with a spring constant of 225 N m as shown in the diagram below The surface is initially frictionless and the spring releases the box as soon as it reaches its natural length Use conservation of energy to answer the following questions k 225 N m 0 00000 m x 0 550 m V1 h 9 55 m s m ty 0m s d 3 50 m m a After the box is released and the spring reaches its natural length what is the velocity v of the hoy 15 noite

Brakes of very small contact area are not used although friction is independent of area because friction 1 Resists motion 3 Depends upon the nature of materials 2 Causes wear and tear 4 Operating in this case is sliding friction

A pulley is attached to the ceiling of a lift moving upwards Two particles are attached to the two ends of a string passing over the pulley The masses of the particles are in the ratio 2 1 If the acceleration of the particles is g 2 with respect to the lift then the acceleration of the lift will be

Chaitanya IIT Academy 16 05 2021 Sr Super60 All Jee Adv 2019 P1 GTA 05 Q P For the arrangement shown in the figure mass of block A is 50 kg and mass of block B is 70 kg Coefficient of static friction between all plane surfaces is 0 3 Find th largest value of mass of block C in kg so that blocks A and B remain at rest Negled friction in the pulleys g 10m s 4 A

Calculate the minimum force applied for which the mass m stays at rest w r t the body of mass M 1 mg fr smooth M L E 2 Zero 3 m cannot be at relative rest

In the arrangement shown in figure if the system is released from rest the acceleration of centre of mass of system is pulley and string are ideal downward 1 3 g downward 2kg 1kg g 3 3 upward 4 upward 5

A light and inextensible string of length 1 20 m tied between two nails supports a frictionless pulley of weight W 10 2 N from which a block of weight W 10 2 N is also suspended as shown in the figure The nails are fixed in a level a distance x 10 2 m apart Radius of the pulley is r 10 cm How much normal reaction per unit of its length does the string apply on the pulley

Two light wires A and B shown in the fig are made of the same material and have radii rA and 3 respectively The block between them has a mass m When the force F is mg 3 one of the wires breaks A A A breaks if r IB B A breaks if r TB C Either A or B may break if r 2rg E B D The lengths of A and B must be known to predict which wire will break Tla S 12

A body kept on a smooth inclined plane inclination 1 in x will remain stationary relative to the inclined plane if the plane is given a horizontal acceleration equal to 1 gx x 1g 2 3 x 1 X g g x

3 0 3 m sec 4 0 3 m sec The velocity acquired by a mass m in travelling a certain distance d starting from rest under action of a constant force is directly proportional to 2 Independent of m 1 m A boduto 4 m

A machine gun fires a bullet of mass 50 gm with velocity 1000 m s If average force acting on gun is 400 N then find maximum number of bullets fired per minute Question Type Single Correct Type 1 2 3 4 240 120 480 8

A Block Sliding Over Another Block on an Incline A block A of mass M on an inclined surface and a weight B is attached to a string as shown in figure Determine the acceleration of blocks A and B after system is released from rest 1 FBD of A FBD of B fa TA AN A forms

2 In the circuit shown in figure C 6 uF The charge stored in capacitor of capacity C is a zero c 40 C C 11 2C 10V b 90 C d 60 C KUL

25 m s A cha AB of length L is lying in a smooth orizontal tube so that a fraction h of its length hangs freely and touches the surface of the able with its end B At a certain moment the nd A of the chain is set free The velocity of nd A of the chain when it slips out of tube is L A B h F 1 12 g

C 10 24 MeV A photon of energy 10 2 eV collides inelastically with a Hydrogen atom in ground state After a certain time interval of few micro seconds another photon of energy 15 0 eV collides inelastically with the same hydrogen atom then the observation made by a suitable detector is A 1 photon with energy 10 2 eV and an electron with energy 1 4 eV B 2 photon with energy 10 2 eV C 2 photon with energy 1 4 eV D one photon with energy 3 4 eV and 1 electron with energy 1 4 eV 2005 mont whose k wavelength is 2 11 The atomic number of an

Suppose two forces a 19 N and a 47 N push an object to the right while a 13 N pushes the same object to the left How large is the net force on the object

When string doesn t slip over the uniform cylindrical pulley of mass 4kg then what is the tension T1 in the left side of the string as shown in diagram The axis of the solid cylinder is horizontal and there is no friction at the axle Take gravitational acceleration g 10m s 1 10 N 3 20 N T M 4 kg 2 kg 1 kg 2 16 N 4 25 N

Astronauts in a spaceship moving with a constant velocity vo observe a massive planet at a great distance also moving with velocity vo at an angle of 120 with the direction of motion of the spaceship The astronauts have to reverse the direction of motion of their spaceship Determine how much maximum speed in reverse direction the spaceship can acquire without expenditure of fuel with the help of gravitational field of the planet us 200

Two bodies A and B of mass 3 kg an contact with each other rest on a table against a rigid wall The coefficient of friction between the bodies and the table is 0 2 when the force of 200 N is applied horizontally on A Which of the following is correct 200 N M O 2 A S B 10 The reaction of wall is 200 N 2 The action reaction force between A and B is more than reaction of wall 3 The action reaction force between A and B is less than reaction of wall 4 Both D and 3 aro

11 A cage with a parrot sitting in it is suspended from a spring balance When the parrot starts flying the reading of the spring balance does not change if it is a closed cage If it is a wire cage the reading decreases If a body is 12 body is zero

The following forces F 10 2 N F 4 61 N act on an object at some insta of time Which of the following statements is are TRUE for the net force on the object A Unit vector in the direction of the net force is 0 61 0 8 N B Unit vector in the direction of the net force is 0 61 0 8 C Angle of the net force vector with the positive x axis is 127 D Angle of the net force vector with the positive y axis is 37

Two masses m and M are attached with strings as shown For the system to be in equilibrium we have 1 tan 0 1 3 tan 0 1 T 45 m 2M m M 2m 45 M T 2 tan 0 1 4 tan 0 1 2m M 2M

127 Two stones are projected with the same speed but s of making different angles with the horizontal Their Bortseranges are equal If the angle of projection of one shoshyors di is and its maximum height is y then the 3 maximum height of the other will be 5 2 20 1 3y on much 9 9 4 2 LOST 3 128 A projectile is thrown from a point in a horizontal 3

A block of mass M is situated on a smooth horizontal friction less table A thread tied to a block passes through a hole in the table and carries a mass m at its other end If the length of the thread above the table is what should be the value of m so that it may remain suspended at a constant height and the block M moves in a circular path with an angular velocity w on the table

A block of mass 2kg is given velocity 5 m s along the horizontal surface which is alternatively smooth and rough Consider first 1 meter is smooth Then A B C D Speed of block when it crosses 2m point is 3 m s Speed of block when it crosses 2m point is 2 5 m s Total distance travelled by block before it stops is 10 m Total distance travelled by block before it stops is 20 m T S 1m 2m 3m 4m

7 On turning a corner a motorist rushing at 40 m s finds a child on the road 108 m ahead He instantly stops the engine and applies the brakes so as to stop it within 1 m of the child what time is required to stop it a 5 4 second b 6 4 second c 3 9 second d 2 second

28 In the arrangement shown in figure mA mB String is massless and pulley is frictionless Block B is resting on a smooth horizontal surface while friction coefficient between blocks A and B is 0 5 What maximum horizontal force F can be applied so that block A does not slip over the block B g 10 m s a 25 N c 30 N A B b 40 N d 20 N F 2 kg

10 Two masses m 5 kg and m 10 k connected by an inextensible string over frictionless pulley are moving as shown in the figure The coefficient of friction c horizontal surface is 0 15 The minimur weight m that should be put on top of m stop the motion is JEE Main 201 a 18 3 kg c 43 3 kg m M T T m 3 m1g b 27 3 kg d 10 3 kg

7180 A rocket with lift off mass of 10 metric ton is blasted upwards with an initial acceleration of 2 2 m s What is initial thrust of blast g 9 8 m s 105 KN 112 KN 120 KN Review 12 KN

Two blocks A and B of masses m and M are placed in a platform as shown in the figure The whole arrangement is placed inside an elevator which is coming down with an accelerationa a g What maximum horizontal force F can be applied to A without disturbing the equilibrium of the system Here is coefficient of friction between the Obetween block B lift floor blocks F m BM 2 mg 2 m g a 2 m g a T a

Paragr A block A of mass 1 kg is kept on rough surface of co efficient of friction 0 5 A light pan Pis attached with a light string ACP to block A The block A is also connected to wall by another thread dm dt B AB Sand particles are poured at a constant rate strike the pan Pwith 10 m s and stop The pouring starts at t 0 g 10 m s T T A The tension T in thread ACP at t 5s A 5 N B 4 N D C 6 N P 1 N 0 1 kg s into the pan P The sand particles

29 A block is kept on a smooth inclined plane of angle of constant inclination 30 that moves with a acceleration so that the block does not slide relative to the inclined plane Let F be the contact force between the block and the plane Now the inclined plane stops and let F2 be the contact force between the two in this case Then F F2 is a 1 c 2 b 4 3 3 2 d

24 A plumb bob is hung from the ceiling of a train compartment The train moves on an inclined track of inclination 30 with horizontal Acceleration of train up the plane is a g 2 The angle which the string supporting the bob makes with normal to the ceiling in equilibrium is a 30 c tan 3 2 b tan 2 33 d tan 2

8 A particle is released from rest from a tower of height 3h The ratio of the intervals of time to cover three equal heights h is a t t t 3 2 1 b t t t 1 3 2 c t t t 3 2 1 d t t t 1 2 1 3 2

13 A small block of mass 1kg is placed over a plank of mass 2 kg The length of the plank is 2 m Coefficient of friction between the block and K 2kg 2m 1kg c 0 62 s F 30 N the plank is 0 5 and the ground over which plank is placed is smooth A constant force F 30 N is applied on the plank in horizontal direction The time after which the block will separate from the plank is g 10 m s a 0 73 s b 1 2 s d 1 6 s

9 Two unequal masses are connected on by two sides of a light string passing over a light and smooth pulley as shown in figure The system is released from rest The larger mass is stopped for a 1kg moment 1 0 s after the system is set into motion The time elapsed before the string is tight again is g 10 m s a 1 4 s b 1 2 s c 2 3 s G d 1 3 s 2kg

25 Assuming the gravity to be in negative z direction a force F v x A is exerted on a particle in addition to the force of gravity where v is the velocity of the particle and A is a constant vector in positive x direction With what minimum speed a particle of mass m be projected so that it continues to move undeflected with constant velocity a A mg c mg i A b A mg d mg A

A block of mass 5 kg is resting on rough surface for which coefficient of kinetic friction is 0 5 When a force of F 60 N is applied the acceleration of block will be g 10 m s 60 N MK 0 5 4 6 ms 3 9 m s 8 2 ms 2 6 ms 37

Two bodies of masses 5 kg and 4 kg are arranged in two different ways as shown in fig A and B If the pulleys and the table are perfectly smooth the acceleration of the 5 kg body in case A and B are respectively 4kg 9 and 5 9 g 4 9 g and 1 9 g CORRECT ANSWER g 5 and g 5 510 m 1 0 5kg 5kg 3 4kg

Two particles of equal mass are connected by a light rod of negligible mass as shown in the figure The rod is rotated about end B in horizontal plane The ratio of tensions in smaller part to other is 2r 94940 B m 1 3 3 2 m

38 A U shaped smooth wire has a semicircular bending between A and B as shown in the figure A bead of mass m moving with uniform speed v through the wire enters the semicircular bend at A and leaves at B The average force exerted by the bead on the part AB of the 2mv b 4mv nd d None of these A B