Newton's law of motion Questions and Answers

A ladder rests against a frictionless vertical wall with its upper end 6m above the ground and the lower end 4m away from the wall The weight of the ladder is 500 N and its C G at 1 3rd distance from the lower end Wall s reaction will be in newton AMU Med 2000 a 111 c 222 b 333 d 129

A ball is projected with velocity Vo at an angle of elevation 30 Mark the correct statement Kinetic energy will be zero at the highest point of the trajectory Vertical component of momentum will be conserved Horizontal component of momentum will be conserved Gravitational potential energy will be minimum at the highest point of the trajectory

3 A force of 0 1176 N acts horizontally for 5 s on a 50 g block kept on a floor What is the velocity attained by the block Coefficient of sliding friction between the block and the floor is 0 2 196 cm s 1

The machine as shown has 2 rods of length 1 m connected by a pivot at the top The end of one rod is connected to the floor by a stationary pivot and the end of the other rod has a roller that rolls along the floor in a slot As the roller goes back and forth a 2kg weight moves up and down If the roller is moving towards right at a constant speed the weight moves up with a Jee Main 2017 A constant speed C increasing speed F 2 kg Timmy T Movable roller X Fixed pivot B decreasing speed 1th of that of the roller when the weight is 0 4 m above the ground

we apply When a car is acclerated force then pseudo force is opposite direction In that it is non innertial frame So when we consider its tota system then it s innertial frame And net force is zero But in this system force has present and accleration also Total system we consider inertial frame and net force is zero

forces of 3N 2N and 1N act on a particle as shown in the figure Calculate the net force along the x axis net force along the y axis and a single additional force required to keep the body in equilibrium A I NNF N 1 N 3 F 2 3 B 2N 3N IN X 3 B N 1 N F 2 NU 3 N

ALLE A uniform sphere is placed on a smooth horizontal surface and a horizontal force F is applied on it at a distance h above the centre The acceleration of the centre of mass of the sphere 1 is maximum when h 0 2 is maximum when h R 3 is maximum when h R 2 4 is independent of h a F

e 4 9 and A stone of mass 0 05 kg is thrown vertically upwards What is the direction and magnitude of net force on the stone KCET 2015 during its upward motion a 0 49 N vertically downwards b 9 8 N vertically downwards c 0 49 N vertically upwards d 0 98 N vertically downwards A ball A is thrown up vertically with a speed u and at the same instant another ball B is released from a height h At time t

6 A man moves on a horizontal road towards east at a speed of 1 km hr and the rain appears to him vertical at a speed of 2 km hr The actual speed of the rain in km hr is 1 1 3 3 2 2 4 5

A constant force acts for 5 seconds on a body of mass 5 quintals and then cease to act During the next 5 s the body describes 100m Find the magnitude of th force a 1000N b 2000 N c 4000 N d 6000 N

The side of a cubical block when measured with vernier calipers is 2 50 cm The vernier constant is 0 01 cm The maximum possible error in the area of one face in cm is 1 0 01 3 0 05 2 0 02 4 0 10

to bring it to rest in 10 revolutions the 29 A cylinder rotating at an angular speed of 50 rev s is brought in contact with an identical stationary cylinder Because of the kinetic friction torques act on the two cylinders accelerating stationary one and decelerating the moving one If the common magnitude of the acceleration and deceleration be one revolution per second square how long will it take before the two cylinders have equal angular speed 36

Answer the following by appropriately matching the lists based on the informatio given in the paragraph block of mass 10 kg is at rest on rough inclined of inclination 37 with help of a constant orce F Force F have magnitude 20 N At t 0 another force F start acting on block Magnitude of force F changes with time as F 10t N Both forces F and F are parallel to inclined and are acting up the inclined Friction force acting on block is f Match the list I and List II III t 10 sec IV t 15 sec 10kg 37 Coefficient of friction between block and inclined is 0 5 List I f I I t 4 sec II t 7 sec A IS II T III Q IV R P II R III S IV T F 20N F 10t P Q List II II f 0 f 30 N R f 40 N S f 60 N T f 80 N U f 100 N B I P II Q III R IV R D I S II Q III R IV P

In an ideal Atwood machine having only two blocks on either side of pulley the sum of two masses is constant If the string can sustain a tension equal to 24 of the weight of the sum of the two masses then the least 50 acceleration of the masses would be in ms 2 g 10ms 2 02 O 5 4

A 6 8 kg block slides down a rough incline with some support from a rope the rope pulls vertically upwards like in the picture below The angle of the incline is 34 degrees and the coefficient of friction between the block and the incline is 0 13 You pull on the rope with a force of 52 N This is NOT a large enough force to lift the block upwards off the incline What is the acceleration of the block in m s

A boy throws a ball vertically upwards then O work is done by the boy only at the moment he throws the ball O work done by boy on it is zero O work is done by the boy throughout the motion of the ball O work is done by the boy only during upward motion of the ball

A simple pendulum of length 50cm and bob s mass 100g is oscillating in the air A damping force f 0 0693 V acts due to air where V is speed of bob At any time it has a amplitude A How much time it will take so that amplitude becomes half of initial value O O O 1 sec 3 sec 2 sec none of these

Elongation in a Rotating Ring A thin ring of radius R is made of a material of density p and Young s modulus Y If the ring is rotated about its centre in its own plane about centre at angular velocity find increase in radius of ring

When light goes from air to water the characteristics that remain uncharged is its O Speed O Wavelength O Frequency O Both 1 and 2

This quest 5 in column I have to be matched with statements p q r s t in column II A block of mass m is kept on rough inclined plane of inclination 0 The angle of inclination varies very slowly then match the column I with column II from A B C D 0 0 to 0 Ich have to be matched Statements A B C T Column l Graph of net reaction force by incline on y axis on the block v s 0 on x axis s k Graph between acceleration of block on y axis v s 0 on x axis will s k Graph between magnitude of friction on y axis v s 0 on x axis s k Graph between magnitude of acceleration on y axis v s 0 on x axis s HK p q r s Column Il 1

78 Two wires of the same material but of different diameters carry the same current i If the ratio of their diameters is 2 1 then the corresponding ratio of their mean drift velocities will be b 1 1 a 4 1 c 1 2 d 1 4 9 Two bulbs consume same power when onerat

In the figure shown the static friction coefficient between all contact surfaces is 1 2 What minimum force applied leftward on block I will move the system Repeat problem if the force is now applied on block 2 2kg 1kg Fin 25 95 al

Surface Which of the following option is incorrect g 10 m s 5 kg 1 The normal force on the block equals its weight because of Newton s second law 2 The normal force on the block is equal to the weight not because of Newton s third law 3 The normal force on the block equals its weight because of Newton s third law 4 The normal force on the block is 50 N

1 A block of mass 1 kg is placed on horizontal surface The reaction force to the weight of the block is 1 The 10 N normal force from the surface 2 The 10 N reaction force from the block on the surface 3 The weight of the earth 4 A 10 N force on the earth

Numerical Value Type 30kg mass of the readings of the machines 1 and 2 given mass each box 15kg mass of man 1 an 2 40kg mass of each weighing machine 5kg are x kgwt and y kgwt then x y is 2

A particle moving with velocity V is acted by three forces shown by the vector triangle PQR The velocity of the particle will P R 1 increase 2 decrease 3 remain constant Q 4 change according to the smallest forco OR

No 12 View In English A wire extends by T mm when a weight W is hanged from it If the wire passes through the pulley and a weight W is attached at one and whereas 3W is attached at the other end then the extension in mm of the wire is 1 2 3 4 Correct Answar 4 Your Answer 1 Status incorrect Add to Bookmark List T 21 21 3 31 2

A pulley system lifts a load of 900 N 0 18 m high while the rope pulling it moves 0 98 m How much force in N must be applied to the rope to lift the load Please input your answer as a positive value with two decimal places Your Answer

If two projectiles of same mass are thrown at an angle of 50 and 40 with the horizontal with same speed then which of the following statement is true 1 Time of flight of both projectile is same 2 Maximum height acquired by the both projectiles is same 3 Horizontal range of both projectiles is same 4 None of these

Physics Part A i Maximum Marks 28 This section has 7 questions Each question has FOUR options A B C and D ONE OR MORE THAN ONE of these four option s is are correct Marking scheme 4 If the correct option s is are selected o 1 partial marks for selecting each correct option 1 In case if selected typed option is incorrect 0 In case if no response is typed selected A particle of mass 5 kg moving in the X Y plane has its potential energy given by U 7z 24y Joule The particle is initially at or has velocity 14 42 4 23 m s the particle has speed 25 m s at t 4sec the particle has an acceleration 5 m s the acceleration of particle is normal to its initial velocity particle has constant acceleration

c 2 1 93 A vertical hanging bar of length L weights 8 kg m and caries a load kN at the bottom The tensile force distance 1 from support of the bar will be a W S L 1 b W s L 1 d c W SL W S L 1 2

A block of mass m is kept on movab wedge of mass M The block of mass m is connected to a light string which is being pulled by a force F perpendicular to the inclined plane Find the acceleration of the movable wedge of mass M a c F M m 37 F M m M 53 b 0 d mF M F

In the arrangement given below the magnitude of tension T in the rope is Assume ropes and pulley are massless and all the surfaces to be frictionless Take g 10 m s T 1 40 N 80 N 3 1 kg AT 2 kg 2 80 N 4 40 N

Suppose a lift is acclerated upward or downward Then pseudo force act opposite to accleration i mean when lift upward pseudo force is downward direction and vice versa Am I right brother 5 32 PM

Two blocks each of mass m lie on a smooth table They are attached to two other masses as shown in the figure The pulleys and strinigs are light An object O is kept at rest on the table The sides AB and CD of the two blocks are made reflecting the acceleration of two images formed in those two reflecting surfaces w r t each other is a 5g 6 b 5g 3 c g 3 3m d 17g 6 m O m 2m

In column 1 a situation is depicted each of Match with appropriate entries in column II Column I A Bead is threaded on a circular fixed wire and is projected from the lowest point B Block loosely fits inside the fixed small tube and is projected from lowest point C Block is projected horizontally from lowest point of a smooth fixed cylinder D Block is projected on a fixed hemisphere from angular position 0 R Im 5m s R Im 20 m s R Im m s 6m s R Im Column II P Normal force is zero at top most point of its trajectory Q Velocity of the body is zero at top most point of its trajectory R Acceleration of the body is zero at the top most point of its trajectory S Normal force is radially outward at top most point of trajectory

View In English A solid conducting sphere of radius a has a net positive charge 20 A conducting spherical shall of inner radius b and outer radius c is concentric with the solid sphere and has a not charge Q The surface charge density on the inner and outer surfaces of the spherical shell will be 4 1 2 3 20 O 4b 4c Q Q 4b 4c Q 4TC None of the above 0

When 100 g of a liquid A at 100 C is added to 50 g of a liquid B at temperature 75 C the temperature of the mixture becomes 90 C The temperature of the mixture if 150 g of liquid A at 100 C is added to 25 g of liquid B at 50 C will be O 80 C O 900 11 1000 11 1100 9 C

A block of mass 2kgis moving on a smooth surface with constant speed A constant horizontal force F acts on the body for 2 s during which its speed increases by 3m s Find F a 2N b 4N c 3N d 1N

A thin uniform rod of mass 5 kg and length 1 m is held in horizontal position with the help of strings attached to ends of rod Other ends of strings are held by some external agent Now end A is pulled down with speed VA 3t and end B is pulled down with speed VB t where t is time in sec Choose the correct choice s at time t 0 A Angular acceleration of rod is 2 rad s B tension in left string is 185 6 N C Acceleration of rod is 1 m s D tension in right string is 170 3 N VB B

One end of rope is fixed to a vertical wall and other end is pulled by a horizonta force of 20N The shape of flexible rope is shown in fig The angle made by tangent at A fixed point of rope with down ward vertical i e is 30 A A Tension in the string at A is 40 Newton B mass of the rope 3 5 kg C The mass of rope is 1 5 kg D Tension in the rone is 20N at fixed point A 20N

A block of mass M is hanged by a ligh spring of force constant k to the top bar o a reverse U frame of mass M on the floor The block is pulled down from it equilibrium position by a distance x and then released The minimum value of such that the reverse U frame will leave the floor momentarily is 000000 k M 1 x M M g k 2 x 2M M g k 3 x M 2M g k 4 x M g k M

Sand is being dropped vertically down ward on a conveyor belt at the rate of 2 kg per second The force necessary to keep the belt moving with a constant speed of 3 ms I will be A 12 N C 18 N B 6 N D Zero

2 56 A ladder is hanging from ceiling as shown in figure 2 220 Three men of masses 10 kg 12 kg and 8 kg are climbing in such a way that man A is going down with an acceleration of 1 6 m s and C is rising up with an acceleration of 0 9 m s and man B is going up with a constant speed of 0 6 m s Find the tension in the string supporting the ladder Ans 291 2 N dount badtelt a to bad or toolbhim Sessie

DA b the curvature radius of 36 A particle A moves in one direction along a given trajectory with a tangential acceleration w at where a is a constant vector coinciding in direction with the x axis Fig 1 4 and T is a unit vector coinciding in direction with the velocity vector at a given point Find how the velocity of the particle depends on x provided that its velocity is negligible at the point x 0 Fig 1 4 O 704 A a X

A block of mass 1 kg is dropped on a spring mass system as shown in the figure The block travels 100 meters in the air before striking the 3 kg mass Calculate maximum compression in the spring if both the blocks move together after the collision Spring constant of the string k 1 25 106 1kg 3kg ell 100m k 1 25x105

A Block of weight 176 N is suspended with the help of a string The block is pulled by a horizontal force F such that the string makes an angle of 8 31 degrees with the vertical as shown in the figure Calculate the magnitude of force F in N A F

c How much force is needed to accelerate an object of mass 7 kg with uniform acceleration of 3 5m s d Why action and reaction forces never cancel each other e Under what condition will the magnitude of the displacement be equal to the distance travelled by an object

2 1 A man of weight W 712 N holds one end of a rope that passes over a pulley vertically above his head and to the other end of which is attached a weight Q 534 N Find the force with which the man s feet press against the floor Ans 178 N Y Fig A P R

An elevator accelerates upwards at a constant rate A uniform string of length L and ma a small block of mass M that hangs from the ceiling of the elevator The tension distance 1 from the ceiling is T The acceleration of the elevator is T 1 3 T M m T ml ml L g 8 2 4 2M m T 2M m ml L ml g g LE I