Newton's law of motion Questions and Answers

A uniform rod of mass M and horizontal plane about a vertical axis with constant angular velocity was shown in figure The tension in the rod at point P is 1 3 Lw P Mo L x L Mw L x 21 M L 2 Mw L x Mw L x 4

A man of mass 50 kg stands on a frame of mass 30 kg he pulls on a light rope which passes over a pulley The other end of the rope is attached to the frame For the system to be in equilibrium what force man must exert on the rope A 30 g C 40 g 8 80 g D 50 g

For a body in a circular motion with a constant angular velocity the magnitude of the average acceleration over a period of half a revolution is times the magnitude of its instantaneous acceleration B 77 C T A 2 T D 2

A body starts with a velocity of 3 m s and moves in a straight line with a constant acceleration If its velocity at the end of 5 seconds is 5 5 m s find i the uniform acceleration and ii distance travelled in 10 seconds

A block of mass m is placed on a smooth inclined wedge of inclination 0 as shown in the figure A force F is applied over the wedge such that block remains stationary over the wedge Value of F is F M m M g m M g cote Omg cosece m Dator

1 A rocket is fired vertically up from the ground with an acceleration 10 m s If its fuel is finished at minute then calculate Maximum velocity attained by rocket in ascending motion Height attained by rocket before fuel is finished c Time taken by the rocket in the whole motion d Maximum height attained by rocket

2kg stone moving with speed 10m s toward right 1kg stone moving with speed 5m s opposite to 2kg stone after collecting both stone are moving toward right side find speed of1kg is 20m s what is the final speed of 2kg stone 9 38 AM

A block of mass 1 kg is kept on a wedge of mass 2 kg One end of the block is connected to wall through a pull arrangement as shown The system is released from rest The wedge moves a distance in t seconds 35 A Speed of the wedge at time tis 5 2 mus ES 10 Spotlight Crux 2020 21 Day 1 In Class Assignment Physic M 2 kg m 1 kg 53

in seconds g 10 m s 4A lift starts from rest at t 0 and moves upwards with constant acceleration of 5 m s At t 2 s a bolt from the ceiling of lift detaches and falls freely If height of lift is 7 5 m then the bolt hits the floor of lift at t ns Find the value of n g 10 m s 1 108 30 Buses ply from city 4 to city R at regular interval of 15 minutes Every bus from A to B moves with constant A

4 A force F 5t is applied on a block of mass 10 kg kept on rough horizontal surface u 0 5 in rest what is speed of the block at t 20 s 1 15 m s 3 25 m s kg F 5t 10 kg 0 5 2 18 m s 4 Cannot be calculated

The arrangement shown in figure If right one block is pulled as shown by a force 2 mg then the acceleration of block A is 1 3 Am m B F 2mg 2 LA 2g 3 g

In one of my physics videos ium app they told me about the horse cart pr oblem in which as the name suggests a hors e pulls a cart and as usual it moves but acco rding to Newton s third law every action has a n equal and opposite reaction which complet ely disproves the horse cart problem but the n they told me that the third law is applicable in a system of two different bodies Now havi ng heard this the horse cart problem makes s ense as the horse is applying force on the gro und and so is the on the horse but my questi on is if we change the system in which i have a bo dy on a table and since the body is kept on t he table the system is at rest as the body is applying a force on the table and so is the ta ble But if I somehow increase the mass of t he body the table won t be able to apply the huge normal force and eventually will break Now why does the table break if every action

To keep a body in uniform motion Options An external force must act An external force may act External force should not act Both 1 and 3 Solution

A force of 5N changes the velocity of a body from 20m s to 30m s in 5s How much force is required to bring about the same change in 2 A O 5N B 10N C O 4N D O 2N

ght from which it was released With what velocity must the body be projected from the ground to reach this height g 9 8 m s2 78 4 m 39 2 m s Q 49 A body thrown vertically upwards is back in the hands of the thrower after 6s How high did it go and where was it 4s after start g 9 8 m s 44 1 m 4 9 m below the top Q 50 A ball is thrown vertically unward from the grou

A conical pendulum is moving in a circle with angular velocity w as shown If tension in the string is T which of following equations are correct mg A skipped B C radius of circle r sine T mw 1 T sine mw 1 T mg cose 4 C MY S C

A man is standing on a rough 0 5 horizontal disc rotating with constant angular velocity of 5 rad sec At what distance from centre should he stand so that he does not slip on the disc A R 0 2 m skipped B C D R 0 2 m R 0 5 m R 0 3 m

A particle is moving in a circle A The resultant force on the particle must be towards the centre B C D skipped The cross product of the tangential acceleration and the angular velocity will be zero The direction of the angular acceleration and the angular velocity must be the same 4 The resultant force may be towards the centre

In the figure the reading of the spring balanced will be g 10 m s 10kg 30 A 0000 C 50 N B 40 N 60 N 2m s 5kg

3 In a rocket of mass 1000 kg fuel is consumed at a rate of 40 kg s The velocity of the gases ejected from the rocket is 5 x 104 m s The thrust on the rocket is 1 2 103 N 3 2 106 N 2 5 104 N 4 2 109 N

A road is banked at an angle of 30 to the horizontal for negotiating a curve of radius 10 3 m At what velocity will a car experience no friction while negotiating the curve A 54 km hr B D 72 km hr 36 km hr 18 km hr Sy X

27 Refer to figure One kg block performs vertical harmonic oscillation with amplitude 1 6 cm and frequency 25 rad s The maximum value of force that the system exerts on the surface is 1 kg y 1 20 N 3 40 N 00000 4 kg 2 30 N Anda 4 60 N

A thermally isolated cylindrical closed vessel of height 8 m is kept vertically It is divided into two equal parts by a diathermic perfect thermal conductor frictionless partition of mass 8 3 kg Thus the partition is held initially at a distance of 4 m from the top as shown in the schematic figure below Each of the two parts of the vessel contains 0 1 mole of an ideal gas at temperature 300 K The partition is now released and moves without any gas leaking from one part of the vessel to the other When equilibrium is reached the distance of the partition from the top in m will be take the acceleration due to gravity 10 ms and the universal gas constant 8 3J mol K 8m

MCQ Single Correct 1 A block of mass 2M is attached to a massless spring with spring constant k This block is connected to two other blocks of masses M and 2M using two massless pulleys and strings The accelerations of the blocks are a a2 and a3 as shown in the figure the system is released from rest with the spring in its unstretched state The maximum extension of the spring is xo Which of the following option s is are correct g is the acceleration due to gravity neglect friction A a2 a a a3 B At an extension of of the spring the 4 magnitude of acceleration of the block 3g 10 connected to the spring is C Xo 4Mg k in the ratio of to the spring is 3g M 5k moooooo 2M aj 3t 1 4 and 1986 M a D When spring achieves an extension of for the first time the speed of the block connected 2 2M 2019

16 In the diagram shown a block is sliding inside a slot made on the inclined plane of a fixed wedge What is the acceleration of the block as it slides in the slot The plane is inclined at angle 0 The angle made by the line along the slot and the line AP is a A g cose B gsin sina C gsin cosa A O D None

A rod of mass m and length is moving between perpendicular smooth walls as shown When rod is at angle 8 with horizontal its end B is moving right with speed v The speed of end A is A Ovtane Ovcote O Read More vcose B X

7 The friction coefficient between the two blocks shown in figure is but the floor is smooth a What maximum horizontal force F can be applied without disturbing the equilibrium of the system b Suppose the horizontal force applied is double of that found in part a Find the accelerations of the two masses F M m mg

When a 4 kg rifle is fired the 10 g bullet receives acceleration of 3 x 106 cm s2 The magnitude of the force acting on the rifle in newton is an 2 120 4 3000 1 Zero 3 300

From the fixed pulley masses 2 kg 1 kg and 3 kg are suspended as shown in the figure Find extension in cm in the spring at instant when 1 kg and 3 kg block have same acceleration k 200 N m g 10 m s 2 kg 1 kg leeee 3 kg

37 One end of a uniform rod of length 1 and mass m is hinged at A It is released from rest from horizontal position AB as shown in figure The force exerted by the rod on the hinge when it becomes vertical is A 3 a mg 2 c 3 mg B 5 b mg 2 d 5 mg

24 A rod of length 1 slides down along the inclined wall as shown in figure At the instant shown in figure the speed of end A is v then the speed of B will be v sin a v sin sin a sin a b c m B v cos B COS d A V COS a cos B

In the arrangement shown in figure if at an instant block 2 is moving in vertically downward direction with speed 10 m s then speed of block 1 sliding on the horizontal surface at that instant will be m s Valve of n is Answer Read More it 2 10 m s

A spring of stiffness k 500 N m is mounted against the 10 kg block If the block is subjected to the force of F 500 N determine its velocity at s 0 5 m When s 0 the block is at rest and the spring is uncompressed The contact surface is smooth F 500 N k 500 N m

WEDGE FRICTION SOLVE A block of mass m is placed on a smooth inclined wedge ABC of inclination 0 as shown in the figure The wedge is given an acceleration a towards the right The relation between a and 0 for the block to remain stationary on the wedge is b a cosece cose X sint d a etano

3 3 A particle projected at angle 600 with speed 10 3 from the point A as shown in the figure At t same time the wedge is made to move with speed 10 3 towards right as shown in the figure a time taken by particle to strike wedge is 2sec b Range on wedge is 20m c Maximum horizontal displacement 10 3 m d Final velocity of particle is 10m s 10 3 10 3 NE 30 60

the particle Ans v 11 42 A shell of mass 5 kg is fired from a gun with a velocity of 280 ms If the mass of the gun 2000 kg resistance to recoil be 700 N Calculate the distance through which the gun recoils 43 A pile driver of mass 700 kg is dronned from a height F 5 Ans 70

3 Figure shows top view of a horizontal surface Two blocks each of mass m are placed on the surface and connected with a string The friction coefficient is for each block A horizontal force F is applied on one of the block as shown in the figure F is maximum so that there is no sliding at any contact 2 mg 3 C If 8 60 F 2 mg T umg A If 0 30 F T umg Top view m B If 0 45 F 2 mg T mg 21 D If 0 60 F 3 mq T umg

The engine of a vehicle delivers constant power If the vehicle is moving up the inclined plane then its velocity must remain constant CORRECT ANSWER must increase must decrease INCORRECT

1 A particle of mass 102 kg is moving along positive x axis under a force of F x k 2 t 0 the position of the particle is at x 1 0 m and is at rest When x 05 m what will be the velocity the particle 10 N

string passing over it is shown in the figure Two monkeys A and B of masses m and 3 m respectively are off moving on string The correct statements are A is moving up with acceleration g then acceleration of B is also g upward A is moving up with acceleration g then B is moving down with acceleration g 3 A is moving down with acceleration g accolorati

Massless pulley and string passing over it is shown in the figure Two monkeys A and B of masses m and 3 m respectively are of moving on string The correct statements are A is moving up with acceleration g then acceleration of B is also g upward A is moving up with acceleration g then B is moving down with acceleration g 3 A is moving down with acceleration g 2 acceleration of B is 50 6 downward

3 Hollow sphere 4 Solid sphere 15 A car weighs 1800 kg The distance betwee its front axle and back axle is 1 8 m centre of gravity is 1 05 m behind front axl The force exerted by level ground on from wheels is g 10 ms 2 NCERT Pg 17 17500 N 2 6500 N 1 3 9500 N 4 1800 N 16 A ring circular of radius 2 m has mass 100 kg It rolls purely along horizontal flo2 so that its COM has speed 20 cm s 1 Th work 1 0 35 rad s 1 2 0 625 rad s 1 3 0 255 rad s 1 4 0 935 rad s 1 For three particles at corners of an centre of mass co triangle Centre of mass of regular shapes

Three identical cylinders each of mass m are arranged as below For this problem the ground and the cylinders are frictionless Now we apply a constant force F directed to the right as shown For what range of F will all three cylinders remain in contact with each other

A horizontal uniform beam AB of length 4 m and a mass of 20 kg is supported at the end B by means of string which passes over a fixed smooth pulley supporting a counterbalancing weight of 8 kg on the othe side What force F when applied at the point A in a suitable direction will hold the beam in stati equilibrium A F 160 N B F 40 19 N C F 200 80 3 N 20kg 530 B 0 8kg

Two bodies of mass 4 kg and 6 kg are attached to the ends of a string passing over a pulley A 4 kg mass is attached to the table top by another string The tension in this string T is equal to www 1 19 6 N 2 25 N 3 TA 10 6 N 4kg uestion Type Single Correct Type T T 6kg

In figure two blocks are separated by a uniform strut attached to each block with frictionless pins Block A weighs 400 N block B weighs 300 N and the strut AB 0 25 under B determine the weigh 200 N If minimum coefficient of friction under A to prevent motion A B C A 30 60 0 4 Correct 0 2 0 8

A mass M of 100 kg is suspended with the use of strings A B and C as shown in the figure where W is the vertical wall and R is a rigid horizontal rod The tension in the string B is W 90 B R A 45 C M 100 kg

A weight of 50 N is supported by three strings in the same vertical plane Two of the strings are inclined at 60 to the vertical and on opposite sides of the vertical The third string is inclined at 30 to the vertical and the tension in it is 20 N Calculate the tensions in the other two strings O 36 5 N and 24 9nN O 32 5 N and 28 9 N O 38 5 N and 26 9 N O 41 5 N and 27 9 N O 33 5 N and 21 9 N

ZOZ A man of mass 60 kg stands on a weighing scale in a lift which is moving upward with a uniform speed of 10 m s The reading on the scale is NCERT I XI Pg 110 2 120 kg wt 4 90 kg wt A rocket with a lift off mass 10000 kg is blasted upwards with an initial acceleration of 2 m s The initial thrust of the blast is 1 Zero 13 60 kg wt 5 4 Neithe Two iden with sam ratio of m balls by u

tatic friction between cyclist does not slip CERT I XI Pg 105 and accelerates minimum value of between surface n it such that box RT I XI Pg 110 4 50 N 13 In the given figure the reading of spring balance is g 10 m s NCERT I XI Pg 100 6 kg 1 10 N 2 20 N 3 80 N 4 40 N mmmmm 3 kg 15 A car is moving on a curved road of R The road is banked at an angle coefficient of friction between tyres of the and road is The minimum safe w INCERT 1 XIP on this road is 1 2 3 4 gR u tane 1 tane gR tan0 1 utane gR tan0 V 1 tane gR tan0 1 utane