Newton's law of motion Questions and Answers

Since Pseudo Force acts opposite to the acceleration of non intertial frame then why don t centrifugal acceleration acts opposite to net acceleration Resultant of Tangentic acceleration and

Find the forces in the hinged rods BC and AC if AB 60 cm AC 1 2 m BC 1 6 m see figure Hanging mass has a mass of 50 kg the mass of the rods can be neglected C is hinge A B A AC is in tension with force of 1000 N 4000 B AC is in tension with force of N 3 4000 C BC is in compression with force of N 3 D BC is in compression with force of 400 N C

A uniform solid cylinder of mass M and radius R rolling without sliding on a rough horizontal plane is pulled at its axis with a horizontal velocity of Vo By means of a string of length 2R attached to its axis the cylinder is dragging a thin plate of mass m 2M lying on the plane If the pulling force is removed and the coefficient of friction between the cylinder and ground is sufficient enough for rolling always u 0 4 Vo 2m sec R 0 5 m g 10 m sec Choose the CORRECT option s before the cylinder comes to rest M G 2R X H A The net force on the cylinder is along positive y direction

A body hangs from a spring balance supported from the roof of an elevator a If the elevator has an upward acceleration of 2 45 m s and the balance reads 50 N what is the true wei of the body b Under what circumstances will the balance read 30 N c What will the balance read if the elevator cable breaks

2 A particle moves towards east with velocity 5 m s After 10 seconds its direction changes towards north with same velocity The average acceleration of the particle is CPMT 1997 AFMC 1999 Pb PET 2000 JIPMER 2001 MP PMT 2013 a Zero 1 c m s N E LIOT J2m1 8 1 d m s S W m s N W

15 The massless inextensible string connecting the slider A and mass B passes over two small massless smooth pulleys one of which is attached to A One of the ends of string is attached to mass B and the other to a fix point P on roof as shown in figure Mass B has a constant velocity vo directed downward At the instant when yA b the magnitude of acceleration of A is given b 1 m and v 2 m s In S I unit YA 18 V

NEWTON S LAWS 25 Two blocks connected by a cord passing over a small frictionless pulley rest on frictionless planes as shown in the figure a Which way will the system move b What is the acceleration of blocks c What is the tension in the cord 100 kg 30 53 50 kg

Two blocks shown in figure are connected by a heavy uniform rope of mass 4 kg An upward force of 200 N applied as shown a What is the acceleration of the system b What is the tension at the top of heavy rope c What is the tension at the mid point of the rope 200N 5kg 4kg 7kg

A ball of mass m is placed on a sledge of mass M The sledge moves on an inclined plane A of angle of inclination 0 Inclined plane A is moving with constant horizontal acceleration a towards left Neglect friction everywhere A Normal reaction force between m M is m gcose asin B Normal reaction force between A M is M m gcose asin C aM A am A gsin0 acos0 2 2 D aMam sin 0 g a a A

What force parallel to a frictionless plane is necessary so that a 60 0 kg object will slide down the plane wi acceleration of 5 0 m s2 if the plane makes an angle of 60 with the horizontal

9 PHYSICS The particle of mass 1 kg is acted upon by a force F F i F from t 0 to 1 4 sec Find the velocity of the particle at t 4 sec if its initial velocity is 1 and the variation of applied force with time is as shown in the graphs Fx N A V 1 1 5 0 2 T sec B V 11 Fy N 5 0 2 C v 10 4 T sec D v 21 10

An empty plastic box of mass m is found to accelerate up at the rate of g 6 when placed deep inside water Hc much sand should be put inside the box so that it may accelerate down at the rate of g 6 Than

Two blocks of mass 4 kg and 2 kg are attached by an inextensible light string as shown in figure Both the blocks are pulled vertically upwards by a force F 120 N Find a the acceleration of the blocks b tension in the string Take g 10 m s

In the arrangement shown in figure the strings are light and inextensible The surface over which blocks placed is smooth Find a the acceleration of each block 14kg 2kg kg F 14N b the tension in each string

A rocket of initial mass 6000 kg ejects gases at a constant rate of 16 kg s with constant relative speed of 11 km s What is acceleration of rocket one minute after the blast Neglect effect of gravity 1 25 m s 3 10 m s 2 50 m s 4 35 m s

If the tension in the cable supporting an elevator is equal to the weight of the elevator the elevator ma A going up with increasing speedID B going down with increasing speeding C going up with uniform speed D going down with uniform speed

The system as shown in the figure is released from rest The pulley spring and string are ideal friction is absent everywhere The speed of 5 kg block when 2 kg block leaves the contact with ground is spring constant k 40 N m g 10 m s wwwwwww 3 0 AxPm s B 2 2m s 5 kg 2 kg T C 2 m s 1 50 D 4 2m s

A stretching force of 10N is applied at one end of a spring balance and an equal stretching force is applied at the other end at the same time What will be the reading of the balance 1 5N 2 10N 3 3 20N 20N 4 0

A force acting on a particle A must change the direction of motion of the particle B must change the magnitude of velocity of the p C must change the momentum of particle D must have its reaction on the particle

A block of mass m is placed on a smooth inclined plane of inclination 0 with the horizontal The force exerted by the plane on the block has a magnitude A mg B mg cose C mg cost D mg tane

7 A person says that he measured the acceleration of a particle to be nonzero while no force was acting on the particle A He is a liar B His clock might have run slow C His meter scale might have been longer than the standard D He might have used noninertial frame

TON S LAWS A body of mass 2 kg moving on a horizontal surface with an initial velocity of 4 m s comes to rest after 2 sec If one wants to keep this body moving on the same surface with a velocity of 4 m s the force required is A 8 N B zero C 2 4 N D 1 2 N

A man weights 80 kg He stands on a weighing scale in the lift which is moving upwards with a uniform acceleration of 5 m s What would be the reading on the scale g 10 m s A zero B 400 N C 800 N D 1200 N

B A light frictionless pulley is suspended with the help of a light spring One end P of a light inextensible thread that passes over the pulley is free and the other end is tied to another light spring that is affixed to the ground at its lower end as shown in the figure Stiffness of both the springs is k 500 N m The free end P is h 10 0 cm above the ground What minimum pull at the end P will bring it to the ground KUPKFORNO

An airplane must achieve a speed of 200 0 km h before it gets to the end of the runway If the runway is 1800 m long what minimum acceleration must the plane have 0 95 m s O 0 78 m s2 1 0 m s 0 86 m s

A man has a mass of 78 0 kg What is his weight on Earth 764 N You are correct Previous Tries Your receipt no is 161 3011 What would he observe his weight to be if he is accelerating vertically in a spaceship at 2g far from gravitational influences

1 Two bodies of mass 4 and 6 kg arc 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 A 19 6 N B 25 N T 4 kg T T 6 kg C 10 6 N D 10 N

05 Three equal weights A B C of mass 2 kg each are hanging on astring passing over a fixed frictionless pulley as shown in the figure The tension in the string connecting weights B and C is A zero B 13 N C 3 3 N D 19 6 N

A truck starts from rest and accelerates uniformly with 2 ms 2 At t 10 s a stone is dropped by a person standing on the top of the truck 6 m high from ground What are the a velocity and b acceleration of the stone at 1 11 s Neglect air resistance

A force produces an acceleration of 4 ms 2 in a body of mass m kg and the same force produces an acceleration of 6 ms 2 in another body of mass m If the same force is applied to m m then the acceleration will be A 10 ms 2 B 2 ms C 2 4 ms D 5 4 ms 2

TON S LAWS Two blocks of masses 2 kg and 1 kg are in contact with each other on a frictionless table When a horizontal force of 3 0 N is applied to the block of mass 2 kg the value of the force of contact between the two blocks is A 4 N B 3 N C 2 N D 1 N

TON S LAWS Two masses 2 kg and 3 kg are attached to the ends of the string passed over a pulley fixed at the top and accelertion in the string in terms of g are A 78 8 9 8 8 B 21g g 8 8 C 218 g 8 5 g 5 5 D 12 8

John is pulling a box forward with a force of 100N and the force forms an angle of 30 elevated from the horizontal The mass of the box is 20kg and the box is at rest at the beginning If the coefficient of kinetic friction is 0 2 and the coefficient of static friction is 0 3 answer the following questions Show your steps g 10m s 1 Determine if the box will start moving Support your argument with relevant calculation 3A 2 the frictional force 2A 3 Determine the acceleration of the mass if it ever starts moving 3A

2 A constant force acting on a body of mass 3 0 kg changes its speed from 2 0 m s to 3 5 m s in 25 s The direction of motion of the body remains unchanged What is the magnitude and direction of the force

ON S LAWS A pebble of mass 0 05 kg is thrown vertically upwards Give the magnitude and direction of net force on the pebble a during its upward motion b during its downward motion c at the highest point where it is momentarily at rest Do your answers change if the pebble were thrown at an angle of say 45 with the horizontal direction Ignore air resistance

26 on the two sides of light string mA 8 Kg ms 10 Kg g 10m s A B 1 If monkey A holds the string tightly B goes down with acceleration 2 m s relative to the string then monkey A feels greater than true weight of his own body 2 If monkey A holds string tightly B goes down with acceleration 2 m s relative string then tension in string is 60N 3 If A holds string tightly and B goes down with acceleration 4 m s relative to string then A feels tr weight of his own body 4 If a holds string tightly B goes down with acceleration 4 m s2 relative to string then both A feels weight equals to 640 9 N 2

5 A disc of mass 1 Kg lies on a smooth horizontal table A light string runs half way around it as shown in figure One end of string is attached to a particle of mass 0 5 Kg other end being pulled with a force F There is no friction between the disc and the string The acceleration of end of the string to which force is being applied is 1 24 m s 2 32 m s 1kg m 0 5kg F 4N 3 8 m s 4 16 m s

A boy of weight 60 kg wt is standing in a lift If the lift beings to move up with a uniform speed 4 9m s the apparent weight of boy is 1 60 kg wt 2 90 kg wt 3 30 kg wt 4 zero

A mass of 5 kg is suspended by a string 10 m long A horizontal force is applied on the mass to pull it 5 m from a vertical line through the point of suspension Find the magnitude of the force Ans 28 29 N 18 One of the recton 1

A force of 5N acts on a body at rest and mass 1kg During this time the body attains a velocity of 30m s The time for which the force acts on the body is 1 10 sec 2 8 sec 3 6 sec 4 5 sec

A rupee coin starting from rest rolls down a distance of 1 m on a plane inclined at an angle of 30 with the horizontal Assuming that g 9 81 ms taken is 1 Correct Answer 3 Your Answer 2 0 32 s 0 48 s 0 782 s 10 s

A block mass mis placed on a table which is moving upwith an acceleration a Then the normal reaction acting on the block is 1 mg 2 m g a 3 m g a 4 mg a

The pulley is light and smooth Strings are inextensible and light Then tension in the string connecting 2kg and 3kg is g 10m s 2kg 3kg 5kg 1 12 N 2 22 N 3 32 N 4 42 N

Find the accelerations of rod A and wedge B in the arrangement shown in Fig 1 20 if the ratio of the mass of the wedge to that of the rod equals n and the friction between all contact surfaces is negligible A a

A 10 kmph south B 10 2 kmph north east 10 2 kmph north D 10 kmph east C Paragraph for Questions 11 13 Consider the setup of block wedge and massless pulley as shown The system is completely at rest and all surfaces are inctionless The wedge is tied to the ground by a clipper m 53 Clipper 14kg 11 The reaction force of wedge over the pulley has a magnitude of B 12 g V5 C 4g D None of these 12 The mass of block on the inclined surface is A 5 kg B 4 kg C 4 kg D A 12 g None of these 13 The horizontal force exerted by the clipper which is holding the wedge to the ground is g 10 m s A 24 N 40 N C ON 50 N B D

Six forces lying in a plane and forming angles of 60 relative to one another are applied to the center of a homogenous sphere with a mass m 6 kg These forces are radially outward and consecutively 1N 2 N 3 N 4 N 5 N and 6 N The acceleration of the sphere is A B C zero 1 m s 1m s

A crane lowers a 134 kg box from rest with a force that varies with time as shown in the graph below Att 10s what is the velocity in m s of the box Be sure to include the appropriate sign in your answer Ft 0 10 5 10 t

9 Find the resultant of the following forces acting at point i 1 2 N along north east ii 9 8 2 N along north west iii 2 kg f along south Given g 9 8 m s 2 Ans 8 8 2 N along SW

A vector A makes an angle 240 with the positive x axis its components along x axis and y axis are b a A and 3 c A 2 2 and 35 3 414 2 d A 2 A 2 3 2 and 3 and 3A

4 86 A rocket ejects a steady jet whose velocity is equal to u relative to the rocket The gas discharge rate equals r kg s Determine the acceleration of rocket in terms of the external force on rocket F and the speed u Ans F ru