Newton's law of motion Questions and Answers

A ship of mass 2 107 kg initially at rest is pulled by a force of 5 105 N throug distance of 2 m Assuming that the resistance due to water is negligible the spee the ship is 1 A 2 ms B 0 01 ms 1 C 0 1 ms D 1 ms E 5

AL In which of the following cases the contact force between A B is maximum m mg 1kg g 10ms 2 1 50 N 2 3 A B A A 30N B B a 35ms a 25 ms

34 Two bodies A and B of masses 5 kg and 10 kg in contact with each other rest on a table against a rigid wall Fig 5 21 The coefficient of friction between the bodies and the table is 0 15 A force of 200 N is applied horizontally to A What are a the reaction of the partition b the action reaction forces between A and B What happens when the wall is removed Does the answer to b change when the bodies are in motion Ignore the difference between and u 200 N Fig 5 21

Which of the following graphs correctly shows the variation in kinetic energy KE of a metal sphere falling freely in a lake Assume sufficient depth of the lake to impart terminal velocity to the sphere d is depth 1 3 KEA 2 KEA 2 4 KE KEA d

1 A small block B is placed on another block A of mass 5 kg and length 20 cm Initially the block B is near the right end of block A figure 5 E3 A constant horizontal force of 10 N is applied to the block A All the surfaces are assumed frictionless Find the time elapsed before the block B separates from A 10 N A

A block is placed on horizontal surface as shown in 16 figure Which of the following statement is correct The normal force on the block is not equals the weight because of Newton s third law 2 The normal force on the block equals its weight because of Newton s first law 3 The normal force on the block is equals its weight because of Newton s second law 4 All of these

m g a In the given figure a smooth parabolic wire track lies in the xy plane vertical The shape of track is defined by the quation yx Aring of mass m which can slide freely on the wire track is placed at the position A 1 1 The track is rotated with constant angular speed o such that there is no relative slipping between the ring and the track The walue of wo is

33 ment if f f and T be the In th frictional forces on 2 kg block 3kg block tension in the string respectively then their values are U 0 1 H 1N 2kg 3kg 8N N 0 2 1 2 N 6 N 3 2 N 2 2 N 6 N ON 3 1 N6 N 2 N 4 data insufficient to calculate the required f 011 er

1 0 6 A block of metal is lying on the floor of a bus The maximum acceleration which can be given to the bus so that the block may remain at rest will be ug H 3 g 4 g g orizontal floor of the compartment of a train running along horizontal rails from left to 2

A particle is projected along a rough plane inclined at an angle of 45 with the horizontal if the coefficient of then the retardation is friction is g 1 2 2 2 802 0 1 G When a horizontal force of F newtons acts on it it

3ft 3T A deflection magetometer is adjusted in the usual way When a magnet is introduced the deflection observed is 8 and the period of oscillation of the needle in the magnetometer is T When the magnet is removed the period of oscillation is To The relation between T and To is AIIMS 2017 T T cos 0 2 T T cos 0 To cose 3 T 4 T T3 cose

A stone is dropped from the top of a tower and it strikes with 3 km hr against the ground Another stone is thrown vertically downwards from the same top of the tower with a velocity 4 km hr Its velocity wher it strikes the ground will be 1 7 0 km hr 2 5 0 km hr 3 3 5 km hr 4 4 0 km hr the top of a tower with a velocity of 10 m sec If the ball fal

A rocket having fuel as its bulk is initially at rest Neglecting effect of gravity when fuel is burning at a constant rate acceleration a of rocket with respect to time is best represented by one of the graphs given below hr min t

7 An Atwood machine consists of a single pulley with masses suspended on each side It is a simplified version of many industrial systems in which counterweights are used for balance Assume that the mass on the right side is 10 kg and that the mass on the left side is 2 kg a What is the acceleration of the system b What is the tension of the cord m 2 kg m 10 kg IM 2 kg

21 Consider a block sliding over a smooth inclined surface of inclination 0 Relating to Newton s second law applied on the block select the incorrect alternative 1 F 0 3 Fx mg sine Luben 2 F 0 4 Fx 0

5 The force acting on a particle F kv k constant If initial velocity of the particle is vo the velocity of particle in terms of time t is 1 v v ekt m vo 3 v v 1 ekt m kt m 2 v v e kt 4 v v 1 e kt m

69 A smooth massless wedge is pushed by a horizontal force P P m 0 Ar tr 1 If P 0 than N mgcos0 N Normal reaction received by the block 2 If P 0 than N mgcose 3 If a 0 than N mgcos0 a acceleration of the wedge 4 If P 0 wedge will accelerate towards left

10 A system consists of two identical blocks each of mass m connected by a massless spring of force constant k Initially the system is in equilibrium as shown in the figure The further compression that must be provided to the spring such that the sigo lower block just lifts off the ground is 1 bos ve zolayd 4 16 etnoms 3 yuzimeno nA ansl9 0 ismin eri 1 2 no 3 BIO 14122 Fubunte 10 vo13 1 insin 4mg k mg co bluorie k E orkom vistos vpoloos ouvent SPES hsb ed bluore XSM 1 ine rase joi sbotic en vinc hsd ii 3mg ko snob sid ton leum show riquo v teoria hewanA no lehoism 629 oosqe ent ni eloric oriths w

12 A horizontal force of 10 N is necessary to just hold a block stationary against a wall The coef ficient of friction between the block and the wall is 0 2 The weight of the block is a 20N c 100 N 10 N b 50N d 2 N

3 Two blocks A and B of mass mA and mg are connected together by means of a spring and are resting on a horizontal frictionless table The blocks are then pulled apart so as to stretch the spring and then released Show that the ratio of their kinetic energies at any instant is in the inverse ratio of thei masses

A person reaches exactly opposite point on the bank of a river if he starts swimming with a speed of 9 kmph at an angle 120 with the direction of flow of the water stream The speed of water in the stream is 1 2 5 m s 2 9 m s 3 4 5 m s 4 1 25 m s Space for Roug

Apparent weight of a man in lift Case I If the lift is at rest or moving uniformly a N mg So Wapp Wapp W actual Case II If the lift is accelerating upwards then Net upward force on man ma N mg ma N mg ma N m g a 187 or N m g a 0 then N actualmg W W app mg AN ing Lift Man d

A bomb of mass 16kg at rest explodes into two pieces of masses 4 kg and 12 kg The velolcity of the 12 kg mass is 4ms The kinetic energy of the other mass is a 144 J b 288 J c 192 J d 96J

Initially spring is relaxed and m is released from rest When m come to rest for a moment string AB is cut at the same moment Find the acceleration of m just after cutting the thread A a m m 20 B a 2m m 000000 m m B A C a m 2m 3m 3m2 1 D a

8 Calculate the maximum possible value of mass m of block Cupto which block A will remain stationary relative to B If the length of block B is equal to 1 50 cm and mass of block C is m3 2mo then calculate the time t when block A will topple from block B if the system is released from rest A B Fig 7 256 C

In the given figure a mass Mis attached to a horizontal spring which is fixed on one side to a rigid support The spring constant of the spring is k The mass oscillates on a frictionless surface with time period T and amplitude A When the mass is in equilibrium position as shown in the figure another mass m is gently fixed upon it The new amplitude of oscillation will be M m a A b A M M c A d A M m M M M mm

Assertion Steel is more elastic than rubber Reason Under a given deforming force steel is deformed less than rubber 1 If both assertion and reason are true and the reason is the correct explanation of the assertion 2 If both assertion and reason are true but reason is not the correct explanation of the assertion 3 If both assertion is true but reason is false 4 If the assertion and reason both are false 5 If assertion is false but reason is true

Select the wrong statement 1 Work done by human heart per beat is 0 5J 2 The energy required to break one bond of DNA is 0 06eV 3 Work energy theorem is the scalar form of newtons second law 4 In a non elastic collision total kinetic energy after collision is always less than total KE before collision

D 7 A train is moving with speed V as shown It crosses a station which has the length 2L as shown The length of the train is L Find out the time in which the train will cross the station A 2L V C L V B 3L V D none V 2L with respect to river is

In the figure there are two particles A B each of mass m A is connected to ceiling by a light inextensible thread OA and E is connected to A by a light inextensible thread AB Initially B is vertically below O and the strings are taut as shown If the system is released from rest immediately after the release tan 37 3 4 O 1379 B A

50 A particle of mass 6 kg moves with an of v 81 81 m s A constant velocit force F 301 N is applied on the particle Initially th particle was at 0 0 The x coordinate of the partic when its y coordinate again becomes zero is give by 1 6 0 m 3 8 m 2 12 8 max 0

30 A solid cylinder of radius 10 cm and length 1m clamped from its one end is twisted through angle 0 4 rad by applying torque at other free end The shear strain developed in cylinder will be 2 0 8 4 0 04 1 0 2 3 0 02 2 bao longth

133 If the block is pulled by the rope moving wit speed v as shown then the horizontal velocity the block is iw nwoint ai eloinsq Ba 1 V 3 V m O V VA V250 9 11 4 em than it has to 2 v cose mart mes 5 1

A man of mass M is on the floor of a lift and lift is moving up with increasing speed with acceleration a then a Normal reaction is more than his true weight b Man appears to be lighter by a g times his true weight O a and b are correct Read More a and b are incorrect O a is correct and b is incorrect

Figure shows a block of mass m moving without friction along three tracks with same speed v Normal reaction R R and R relates as TR TD R R R 43 R R R R R 2 R R R R R R

A cylinder of radius R is kept embedded along the wall of a dam as shown Take density of water as p and length of cylinder as L The pgLR Find the X vertical force exerted by water on the cylinder is value of X

In the figure shown find the accelerations of blocks A B and C immediately after string connecting between block B and block C is cut A a 3g ap g ac gl 5 a 301 a a 0 m A eeeeee m B m C B a 2g ag ac 0 R a 0 a 0 a gl

133 The system shown in figure is just on the verge of slipping The coefficient of static friction between the block and table top is 40 N A 0 5 C 0 15 myy 30 Ow 8 0 W 8 0 N B 0 95 D 0 35

Two stones are projected with the same speed but making different angles with the horizontal Their ranges are equal If the angle of projection of one is 3 and its maximum height is Y1 then the maximum height of the other will be A 3y1 C y 2 B 201 D y 3

Three masses 2 kg 7 kg and 4 kg are connected to each other with threads and are placed on a table as shown in the figure The masses of the pulleys and the threads ar negligible Find the acceleration with which the system is moving in m s 2 kg T A 0 65 m s B 1 54 m s C 3 34 m s 7 kg 4 kg

8 In Young s double slit experiment the slits are 2 mm apart and are illuminated by photons of two wavelengths A 12000A and 10000A At d what minimum distance from the common central bright fringe on the screen 2 m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other a 6mm c 3mm NEET 2013 4mm b d 8mm c

A uniform rope of length L lies on a table If the coefficient of friction is p the maximum fractional length of the hanging part of the rope from the edge of the table without sliding down will be O 1 Read More 4 1

An object is kept on a smooth inclined plane of inclination 0 The horizontal acceleration to be imparted to the inclined plane so that the object is stationary relative to the incline is A gsine C gtane B gcose D gcote

11 For a ballistic pendulum if the length L 1 9 meter angle of deflection from vertical 0 17 4 degree the mass of the bullet m 27 gram and the mass of the catcher M 591 gram the velocity m s of the bullet is

A ball released from the top of a tower travels 11 36 of the height of the tower in the last second of its journey The height of the tower is Take g 10 ms 2 A 11 m C 47 m B 36 m D 180 m

n an explosion a body breaks up into two pieces of unequal masses In this case O Both parts will have equal kinetic energies Lighter part will have more momentum Heavier part will have less momentum O Lighter part will have more kinetic energy

The distance of point of a compound pendulum from its centre of gravity is the time period of oscillation relative to this point is T If g n the relation between and T will be 1 e x 0 2 1 1 x 0 K 0 3 uspension and centre of oscillation for a compound pendulum is 1 0 l k 0 4

A body of mass 5 kg at rest on smooth surface is acted upon simultaneously b two forces 3 N and 4 N at right angle to each other The kinetic energy of body the end of 6 s is 60 J 80 J 85 J 90 J

A block of mass 2 kg is kept on the floor The coefficient of static friction between block and floor is 0 2 If a force of 3 N is applied on block as shown in diagram the frictional force between block and floor is F 3N 2 kg 02N 03 N O4N O Zero

A man pulls a 20 kg mass slowly upwards with the help of light string passing over a frictionless pulley as shown in figure The normal reaction by floor on th feet of man is g 10 m s M 50 kg 20 g mg 750 N 300 N 200 N 600 N