Newton's law of motion Questions and Answers

19 20 21 Paragraph for Question No 19 to 22 A uniform rope of mass m and length L placed on frictionless horizontal ground is being pulled by two forces F and F at its ends as shown in the figure As a result the rope accelerates toward the right A B Acceleration A of the rope is A zero B a F FB m Tension T at the mid point of the rope is A T FB FA B T F FB F F x FB L C a FA F m Expression T of tension at a point at distance x from the end Ais A T F F x F FB B T L C T D T Fa F x F L D a C T F F D T F F L F F m x F in 1774005 Call 0744 2799900 31

Ex A uniform rod AB is freely movable on a rough inclined plane whose inclination to the horizon is a and whose coefficient of friction is u about a smooth pin fixed through the end A the bar is held in the horizontal position in the plane and allowed to fall from this position If e be the angle through which it falls from rest show that sin 0 cot a

A hollow tube containing a ball is kept on smooth horizontal surface Now tube is accelerated horizontally and ball is slightly displaced from point A Let N and N be the magnitude of normal force applied by inner and outer surface respectively Then which of the following is are correctly represent approximate nature of N and N Vs 0 0 0 A C N A N A TC TC 0 B N A D N TC 0 B ao A

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 wire is 1 O 2 4mv nd A B

The position of a particle is given by 7 3t 21 5k where t is in seconds and the coefficients have the proper units for F to be in metres The direction of velocity of the particle at 1 1 sis a 53 with x axis c 30 with y axis b 37 with x axis d 60 with y axis

Question 3 A uniform rigid rod of mass m length I is released from vertical positio on rough surface with sufficient friction for lower end not to slip as shown in figure When rod makes angle 60 with vertical then find correct alternatives m a a 24 b 372 3g c N mg 16 dal 39 4 ITT

given 101 If the coefficient of friction between the block of mass 5 kg and wall is 0 5 then minimum force F required to hold the block with the wall is g 10 m s NCERT Pg 101 max 0 3x3x10 gN f max 65 5N 1 10 N 0 FL 5 kg 0 5 2 100 N

SolveLancer Test A block of mass 10 kg is placed on an inclined plane having inclination 20 with coefficient of static friction is 0 5 and coefficient of kinetic friction is 0 4 Determine the acceleration of block when it release g 10 m s SolveLancer Test a 1 m s b 2 m s b 0 m s b 3 m s

SolveLancer Test 20 m s Car 10 m s Car B 20 m In the above figure what is the speed of image of B observed by A in a rear view mirror of focal length 1 m SolveLancer Test a 0 023 m s b 0 046 m s c 19 04 m s d 9 52 m s

The magnitude of the net force exerted in the x direction on a 4 00 kg particle varies in time as shown in the figure below A 1 a Find the impulse of the force over the 5 00 s time interval N S b Find the final velocity the particle attains if it is originally at rest V m s M c Find its final velocity if its original velocity is 3 00 i m s m s d Find the average force exerted on the particle for the time interval between 0 and 5 00 s N

0 A 25 N force is applied to the block as shown in figure Choose the CORRECT option if initial velocity of block is zero Take g 10 m s 37 2kg 25N 20 25 fa Hg 0 5 HF 0 4 A Normal contact force is 10N B Friction force is 8N C Friction force is 10N D Block is in equilibrium g 10 m s a fac 4 37 2kg 25N A B I C EUT10N D Mg 0 5 HF 0 4

Two bodies are connected by massless string as shown in figure The acceleration of system and tension in string will be F 8 N 14 3 4 kg T T 14 3 m s 28 N 2 m s 12 N 2 m s 16 N m s 20 N 2 kg F 20 N

D A person holding a rifle mass of person and rifle together is 100 kg stands on a smooth surface and fires 10 shots horizontally in 5 s Each bullet has a mass of 10 g with a muzzle velocity of 800 ms 1 The final velocity acquired by the person and the average force exerted on the person are 2 0 08 m s 1 16 N 4 1 6 m s 1 16 N 1 1 6 m s 1 8 N 31 08 m s 1 16 N

c 52 A rod of mass 5 kg is connected to the string at point of rod is along horizontal The other end B The span of the rod is hinged at point A If the string is massless then the reaction of hinge at the instant when string is cut is Take g 10 ms 2 b 12 5 N a 10 1 N UP CPMT 2015 d 15 N with a constant velocity parallel to c 5 N

54 A mass of 1 kg is thrown up with a velocity of 100 m s After 5 second it explodes into two parts One part of mass 400 g moves down with a velocity 25 m s Calculate the velocity of other part just after the explosion g 10 ms 1 40 m s 2 40 m s 3 100 m s

Q7 A block of mass m is placed on the top of another block of mass M as shown in the figure The coefficient of friction between them is u m a g M The maximum acceleration with which the block M may move so that m also moves along with it is M b g m m c g M

Two blocks of masses 3kg and 4kg are placed on the frictionless surface as shown in the figure A force of 10 N is applied on the 3kg block Find the force of contact between the blocks O O O F 10N 30 40 12 N N N 3 kg 4 kg

Match the entries given in column A with the appropriate ones in column B with the help of the figure The coefficient of friction between both the surface of the block and the ground is 0 1 Take g 10 ms 300N O 7777 O M 12 kg Column A Column B A Normal reaction force exerted by the ground a 20 N on the block N is N 8 kg B Net force acting on block N C Acceleration of the system D frictional force acting on the system Ac Bd Ca D b Ac B a C d D b Ac Bd C b D a Aa Bc Cd D b b 14 ms 2 c 78 4 N d 112 N

Sliding on a Conveyer Belt A block of mass mis projected horizontally on a conveyer belt of length I on two small rollers moving at speed v Find the speed at which the block is projected so that the heat dissipated against friction will be maximum also find this maximum heat

On a long horizontally moving belt a child runs and fro with a speed 9 kmh with respect to the be between his father and mother located 50 m apa on the moving belt The belt moves with a speed 4 km h For an observer on a stationary platfora the speed of the child running in the direction motion of the belt is a 4 km h c 9 km h b 5 km h d 13 km h

Figure shows horizontal forces acting on the block that is sliding to the right across frictionless floor If F F which kinetic energy versus time graph is correct F F KE 4 KE K KEN

Q 29 Springs A B and C shown in figure are identical A 1 kg block attached to the lower end of A descends by 1 0 cm A 2 kg block attached to the lower end of C will descend by fesse fe i me 1 kg a 0 5 cm b 1 0 cm 2 0 cm d 4 0 cm Ans D exe 2 kg

c 48 8 km d 58 8 km 89 A police van moving on a highway with a speed of 30 km h fires a bullet at a thief s car speeding away in the same direction with a speed of 192 km h If the muzzle speed of the bullet is 150 m s with what speed does the bullet hit the thief s car a 95 ms c 115 ms b 105 m d 125 ms

Block A is on a frictionless horizontal table A massless inextensible string fixed at one end passes over a smooth nail fixed with the block A The other end of the string is connected to block B of mass m Initially the block B is held at rest so that 0 30 What will be the magnitude of acceleration of block B just after it is released in m s take g 10 m s Temal 1 ma a a 2 N j 600 a 300 A 10 PIP B m 0 3 P m

MtG Objective NCERT Physics 5 A stone is dropped from the top of a tall cliff and n seconds later another stone is thrown vertically downwards with a velocity u Then the second stone overtakes the first below the top of the cliff at a distance given by a c 2 u 8n 2 u gn U 2 11 gn gn b d gn 2 u gn 14 gn gn Motion in a Stra with resp equation a x x c x x

had the mass mo neglected A flatcar of mass m starts moving to the right due to a constant horizontal force F Fig 1 46 Sand spills on the flatcar from a stationary hopper The velocity of loading is constant and equal to u kgs Find the time dependence of the velocity and the acceleration of the flatcar in the proce loading The friction is negligible small Fig 1 46

In the system shown in figure the mass 30 kg is pulled by a force of 200 N At the instant when its acceleration is 7 m s in forward direction what is magnitude of acceleration of 15 kg mass 7 ms 15 mm 30 200 N 1 6 m s 0 66 m s 1 9 m s 3 66 m s

on of of c 16 ms 8 ms d 30 ms 15 ms 66 A body sliding on a smooth inclined plane requires 4 seconds to reach the bottom starting from rest at the top How much time does it take to cover one fourth the distance starting from rest at the top b 4 s d 16 s a 1s c 2 s

27 A cricket ball is thrown at a speed of 28m s in a direction 300 above the horizontal Calculate a the maximum height b the time taken by the ball to return to the same level and c the horizontal distance from the thrower to the point where the ball returns to the same level 3

and the during er the 12 s 62 A girl standing on a stationary lift open from above throws a ball upwards with initial speed 50 m s The time taken by the ball to return to her hands is Take g 10 ms a 5 s c 15 s b 10 s d 20

In the given figure the co efficient of friction between the block and the incline plane is 1 The acceleration with which the system should be accelerated so that the friction between the block and the wedge becomes zero g 10 m s is

3 50 N 4 60 N Calculate the maximum acceleration of M for wh all the bodies move together considering smc surface everywhere 1 mig m m M m 2 M m g

Consider the following charged suspended ball system If a then the statements which can be true at equillibrium out of followings A m m m m m m c Q Q m m d Q Q m m a Q b Q Q Q Q 1 Only d 3 c d 2 Only c 4 b d

32 If K and K are maximum kinetic energies of emitted when lights of wavelength and incident on a metallic surface If 32 photoelectrons A respectively then a K K 3 c K 3K b K K 3 d K 3K

The masses of blocks A B and C are 1 kg 2kg and 0 5 kg respectively All surfaces are smooth If force F 50 N acts as shown At the instant shown the force which A exert on B is C 1 100 3 N F A 2 B 200 3 N

A cliff diver plunges 42 m into the crashing Pacific landing in a 3 metre deep inlet The position of the diver at any time t is given by the equation below W is the average velocity of the diver over the interval 0 2 s t 4t 42 A 11 m s B 9 8 m s C 8 9 m s D 19 6 m s

A particle P of mass mis attached to a vertical axis by two strings AP and BP each of length 1 The separation AB 1 P rotates around the axis with an angular velocity The tensions in the two strings are T and T respectively Then A A T T B T T mo 1 C T T 2mg B 1 D BP will remain taught only if oz 2g 1 P

Top View A spring has a force constant of 100 N m and an unstretched length of 0 07 m One end is attached to a post that is free to rotate in the center of a smooth table as shown in the top view above The other end is attached to a 1 kg disc moving in uniform circular motion on the table which stretches the spring by 0 03 m Friction is negligible 14 What is the centripetal force on the disc 0 3 N 3 N il com 2018 abarc 2 W 10 N 300 N E 1 000 N moooooo 15 What is the work done on the dise by the spring Auring one full circle A B OJ 94 1

A layer of castor oil 1 mm thick is spread on horizontal floor A block is placed on floor and pulled horizontally at constant speed of 2 ms 1 The face of block touching surface has an area of 20 cm and coefficient of viscosity of oil is 10 poise The force applied on block parallel to surface is 10 N 6 N 5 N

10 3 A stone of mass 1 kg tied to a light inextensible string of length L 1m is whirled in a circular path of radius L in a vertical plane If the ratio of the maximum tension in the string to the minimum tension in the string is 4 and if gis taken to be 10m s the speed in m s of the stone at the highest point of the circle is

Figure shows a uniform disc whose mass M is 2 5 kg and radius R 20 m mounted on fixed horizontal axle A block whose mass m 1 2 kg hangs from a massless cord that is wrapped around rim of disc The acceleration of the falling block is g 10 m s M R m 4 9 m s 2 3 9 m s 2 6 2 ms 2 1 8 m s 2

Provided a racing car does not lose traction the time taken by it to race from rest through a distance depends mainly on engine s power P Drive the time t in terms of S and P assuming that power is constant 9 ms 8 P 9 ms 4 P 9 ms 000 1 6 2 1 2 8 P 16 1

1 Block A is in equilibrium Now block A given velocity V g direction Maximum normal reaction on block B is A 3mg 3mg 2 Mohit says that Gauss s I w co C 2 B 4mg D 2mg in downward

View in English A block whose mass is M 30 kg is pushed across a frictionless surface by a stick whose mass is m 2 kg The block is moved from rest a distance of 3 meter in seconds at constant acceleration With what force does stick push on block m M O 40 N O 42 N O 45 N O 48 N smooth

A block whose mass is M 30 kg is pushed across a frictionless surface by a stick whose mass is m 2 kg The block is moved from rest a distance of 3 meter in 2 seconds at constant acceleration With what force does stick push on block smooth 40 N 42 N 45 N M 48 N

c 12 10 N 14 Sand falls on to a conveyor belt at a constant rate of 2kg sec If the belt is moving at 0 1 m sec Then the extra force required to maintain speed of the belt is a 2N 0 2N c 20N d zero

A 75 kg man stands on a spring scale in an elevator During the first 3 seconds of motion from reset the tension T in the hoisting cable is 8300N Find the reading R of the scale in newton during this interval and the upward velocity v of the elevator at the end of the 3 seconds The total mass of the elevator man and scale is 800 kg

A framed structure is perfect if it contains members equal to a 2n 3 b 3n 2 c 2n 1 d n 2 In the figure A2 angle a compared to will be a Greater b Lower c Same d Unpredictable pg Figure A

The three forces keep acting at a point are in equilibrium then a The forces must be coplanar c The forces must be of equal magnitude b The forces need not be coplanar d The forces must be of unequal magnitude

uniform speed U Pulleys A and B are 5 PY JB M A 2 U cos 9 B U cos 9 C 2 U cos 9 Ulcos 9 por A system is shown in the figure A man standing on the block is pulling the rope Velocity of the string in contact with the hand of the man is 2 m s downwards The velocity of the block will Assume that the block does not rotate