Newton's law of motion Questions and Answers

By his weight a man is applying the pressure p Nm 2 on the ground The weight of his child is half of his weight How much pressure will the man apply if he is carrying his child on his shoulder O 2p 3p 2 O 3p O 5p 2

The mass of a body measured by a physical balance in a lift at rest is found to be m If the lift is going up with an acceleration a its mass will be measured as Question Type Single Correct Type 1 m 1 3 2 m 1 3 m

A pull of 80 N is applied in the direction as shown in the figure A constant frictional force 30 N is opposing motion The mass of block is 5 kg The acceleration of block is 80 N F 5 kg 4 3 m s 5 6 m s 6 8 m s 2 3 m s 37

F 200 lb b Stanchion c 295 lb d 430 lb e 1 010 kg Fy 400 lb 30 IN 2 For stanchion figure b if FR F 350k Fi Fyj F k 200j 200i 346 4j where F Fi Fyj F k then the magnitude of F is nearest a 350 N b 570 N NOT CO

Two weights w and we are suspended from the ends of a light string passing over a smooth fixed pulley If the pulley is pulled up at an acceleration g the tension in the string will be 1 3 4w W W W W W W W 2 2w w W W 4 W W 2 w w

A person having a mass of 64 kg rides on a circus Ferris wheel that takes him around a vertical circular path with a radius of 20 m The wheel makes 3 2 revolutions every 264 s WE is the magnitude of the normal force in Newton acting on the person at the highest point on this trajectory Round the answer to three significant figures Top

A rocket from launching pad is set for vertical lift off The exhaust speed is 1500 m s How much gas must be ejecte per second to just lift off the rocket Mass of rocket is 6000 kg g 10 m s 112 kg s 92 kg s 49 5 kg s E 40 kg s

A body of mass 3 kg is launched up a rough inclined plane making angle of 45 with horizontal What is coefficient of friction between body and incline plane if time of ascent is half of the time of descent 0 60 0 42 0 75

A graph is drawn between force acting and time for which i acts on particle The area under the curve between time interval t and t2 gives Momentum of particle Force acting on particle Change in momentum of particle Acceleration of the particle

7 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 strings are light An object O is kept at rest on the table The sides AB 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 3m Bry 2m burz d 17g 6

Five coplanar forces are acting on a particle of mass m such that the angle between any two adjacent forces is 72 Four forces are of magnitude F and one of F The resulting acceleration of particle is 2 Zero 1 F F m F 4F1

A disc of mass m is connected to an ideal spring of force constant k If disc is released from rest then what is maximum friction force on disc in N Assuming friction is sufficient for pure rolling fmmm Dise of mass M 1kg Radius R 0

1 1 A trolley T of mass 5kg on a horizontal smooth surface is pulled by a load of 2kg through a uniform rope ABC of length 2m and mass 1kg As the load falls from BC 0 to BC 2m its acceleration in m s changes from 77 20 T 20 20 30 to 6 5 30 A J 2 B 2kg C 20 30 to 8 8

11 System shown in figure is released from rest Pulley and spring is massless and friction is absent everywhere The speed of 5 kg block when 2 kg block leaves contact with ground is Take force constant of 5 kg spring k 40 N m and g 10 m s a 2 m s c 2 m s b 2 2 m s d 4 2 m s reelle 2 kg

Block B of mas 2 kg is placed on smooth horizontal plane Block A of mass 1 kg is placed on block B The coefficient of friction between A and B is 0 40 The A is imparted a velocity 16 m s at t 0 Find the time at which momentum of the blocks are equal in second g 10m s A B 16m s

uniform annular disc of outer radius R and inner radius r is coaxially nounted on a fixed cylinder Radius of the cylinder is slightly smaller han inner radius of the disc to allow the disc to rotate as a pulley and the fixed cylinder as an axle Coefficient of friction between the disc and the cylinder is A light inextensible rope supporting two loads of nasses m and M m passes along the upper half periphery of the disc Find the acceleration a of the load M Acceleration of free fall is g 15 m M

A horizontal plane supports a plank with a bar of mass m 1 0 kg placed on it and attached by a light elastic non deformed cord of length 1 40 cm to a point O Figure The coefficient of friction between the bar and the plank and elastic constant of cord both equal k 0 20 The plank is slowly shifted to the right until the bar starts sliding over it It occurs at the moment when the cord deviates from the vertical by an angle 0 30 Find the work in jouls that has been performed by that moment by the friction force acting on the bar in the reference frame fixed to the plane m lo

1 mole of an ideal monoatomic gas undergoes the following operations V L IV T K Select the correct statement s from the following In process I Il enthalpy change is positive In process II III work done is zero Work done during the process III and III to I is zero Internal energy change of the procop

44 1 1 92 2 252 3 3 52 4 45 A 14kg block is hanged using a system of 44 pulleys as shown in figure Tension in string connecting celling and topmost pulley is 1 17 5 N 3 140 N In the circuit chour 14 kg 2 70 N 4 280 N AL 1 122 14 ER FER s 2 22 1 17 5 N 3 140 N 14 kg

A block of mass m is kept on frictionless plank as shown in figure below If plank is pulled with a horizontal acceleration a then maximum compression in the spring is spring constant of spring is k 1 3 mg k 2ma k mmmmm m 2 ma k 2mg k a

A person of mass 60 kg is standing on a spring balance in a lift Lift is connected with cable rotar to control the speed of lift there s an arrangement of break and accelerator in it In this conditions select the proper answer in a questions given below g 10 ms 27 What is the observation of spring balance when lift is moving with acceleration of 5 ms in upward direction A 300 N C 100 N D Zero B 200 N

A traffic light hangs from a pole as shown in the figure Figure 1 The uniform aluminum pole AB is 7 90 m long and has a mass of 11 0 kg The mass of the traffic light is 24 5 kg Figure 3 80 m C 37 D 1 of 1 HOOO B Part A Determine the tension in the horizontal massless cable CD FT Submit Part B VA O Request Answer VA O Determine the vertical and horizontal components of the force exerted by the pivot A on the aluminum pole Enter your answers numerically separated by a comma S t N O

C A massive bead is threaded on a long light rod one end of which is pivoted to a fixed point O Initially the rod is held horizontally and the bead is at a distance I from the pivot Coefficient of friction between the rod and the bead is u Which of the following statements correctly describe relation between angle that the rod makes with the horizontal after the rod is released and time t 1 a If u is negligible tan b If u is finite tan 1 gt 21 gt 21 c If u is finite is smaller than tan 1 gt 21 d None of the above statements is correct by a finite amount

In the figure shown a block of mass 10 kg is kept on top of a 20 kg block which is kept on smooth horizontal surface Coefficient of friction between 10 kg and 20 kg block is 0 08 What is the maximum force F in Newton so that system remains at rest 100 N 10 kg 20 kg

fest 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 a 1 m s b 2 m s b 0 m s b 3 m s

Derive the relation between the acceleration of the masses m 5 kg and m 10 kg in the arrangement shown in figure III 1 Also find the magnitude of the acceleration of both masses Coefficient of friction between the mass my and my with the surface is 0 25 and 0 20 respectively 50 m T 1 70 m

21 Two bodies A and B of masses 10kg and 15kg respectively kept on a smooth horizontal surface are tied to the ends of a light string IfT represents teh tenstion i the string when a horizontal force F 500N is appleid to A as shown in figure1 and T be the tension when it is applied to B figure2 then which of the following is true A T T 500N B T T 250N C T500N T 300N D T 300N T 200N F 500N mm 10kg A 10kg A Image 1 15kg B Image 2 15kg B F 500N

32 A trolley is being pulled up an incline plane by a man sitting on it as shown in figure He applies a force of 250 N If the combined mass of the man and trolley is 100 kg the acceleration of the trolley will be sin 15 0 26 250 N 26

A resting on a smooth horizontal plane is attached by threads to a point P and by means of a weightless pulley to a weight B possessing the same mass as the bar itself A B Besides the bar is also attached to a point O by means of light non deformed spring of length 50 cm and stiffness x 5 mg 10 where m is the mass of the bar The thread PA having been burned the bar starts moving Find its velocity in m s at the moment when it

14 Three blocks of masses m m and m are connected by strings on a frictionless inclined plane making an angle 0 with the horizontal m3 Ans 0 m2 Fig 11 43 Problem 14 A force F is applied upwards along the inclined to the uppermost block of mass m to pull the block upwards What is the acceleration of the blocks and tension in the strings F m m m3 g sin0 m m F m m m m m m 9

Football A football is kicked 5 6 1 point When the player s foot is in contact with the football he s doing work on the ball True False 1 point When the football leaves the player s foot he s still doing work on the ball True False 1 point Check all the forces that s doing work on the ball while it s flying in the air Select all that apply player air gravity Sun 610000

An elevator cab and its load have a combined mass of 2000 kg Find the tension in the supporting cable when the cab originally moving downward at 10 m s is brought to rest with constant acceleration in a distance of 50 m

A rope is wound around a hollow cylinder of mass 3 kg and radius 40 cm What is the angular acceleration of the cylinder if the rope is pulled with a force 30 N 1 0 25 rad s 2 2 2 25 rad s 3 5 ms 2 4 25 m s 2

A horizontal bar of mass m and Prism of mass m can move as shown There is no friction at any contact point During the motion the length of the rod is always horizontal Now magnitude values of Smooth wall m m 0 Smooth surface A Acceleration of m is g 1 ncot e where n m m g tan 0 B Acceleration of m is n 1 tan 0 where 2 n m m C Acceleration of m is g tan 0 n cot 0 where n m m g tan 0 D Acceleration of m is n 1 tan 0 where

A rollercoaster has a vertical loop of radius of 20 m Please answer the following and show the work Thank you a Determine the linear acceleration tangential acceleration of the roller coaster halfway up the roller coaster loop

T M T m 4 Two blocks of masses m and m are connected by a massless string that passes over a wheel of mass m as shown above The string does not slip on the wheel and exerts forces T and T on the blocks When the wheel is released from rest in the position shown it undergoes an angular acceleration and rotates clockwise Which of the following statements about 7 and 7 is correct A T T because the wheel has mass B T T because both blocks have the same acceleration C T T because m is farther from the wheel than m D T T because m accelerates upward E T T because an unbalanced clockwise torque is needed to accelerate the wheel clockwise

A force F is applied to a cube placed on a rough surface as shown in the figure The cube is still at rest Select the correct option F A the frictional force is equal to F in magnitude B normal reaction cancels the weight of the cube C normal reaction is equal to the weight in magnitude D all of the above

7 A body of mass 2 kg is sliding with a constant velocity of 4 m s on a frictionless horizontal table The force required to keep the body moving with the same velocity is 1 8 N 2 ON 3 2 x 10 4 N 4 2N

XV particle A is mounted on a light rod pivoted at O and therefore is constrained to move in a circular arc o radius r If the velocity of A in terms of the downward velocity vs of the counterweight for 0 30 is Avg 3 3 then find x B y

SAMPLE PROBLEM 3 5 A flat bed cart of mass me 360 kg rolls on frictionless wheels Resting on the cart is a box of mass MB 150 kg Fig 3 18a The box can slide on the cart but each exerts a force due to friction on the other during the sliding When a worker pulls on the box with a force FBw both the box and the cart move forward but the box moves faster than the cart because the frictional force is not strong enough to prevent the box from sliding forward on the cart An observer measures the magni tudes of the accelerations to be 1 00 m s2 for the box and 0 167 m s2 for the cart Find a the frictional force between the box and the cart and b the force that the worker is exerting on the box PORN

Ag Vg Vg 30 A particle is executing SHM according to the equation x Acos t Average speed of the particle TU during the interval 0 t 6w a c 3Aw 2 3 Aw T Vg 3 Aw 4 d none of these b

A platform of mass m and a counter weight of mass m M are connected by a light cord which passes over a smooth pulley A man of mass M is standing on the platform which is at rest If the man leaps vertically upwards with velocity u find the distance through which the platform will descend Show that when the man meets the platform again both are in their original positions

a b On frictionless horizontal surface 2 blocks are kept as shown The string connecting them is massless When the string is pulled by force F then what is acceleration of point A on string SolveLancer Test c 6 m 5F m 5F 2m F 10m d 4 m A

SolveLancer Test Position of a particle having weight 20 N is given by s 3t 2t 9 The momentum of the particle is 16 Kg m s at any time t The value of t is SolveLancer Test a 3 Sec b 2 4 Sec c 1 Sec d 4 2 Sec Take g 10 m s

QA body is thrown up with a velocity of 100 m s It travels 5 m in the last second of its journey If the same body is thrown up with a velocity of 200 m s how much distance in metre will it travel in the last second g 10 ms A 3 B 5 C 15

2 Three blocks each of mass m are hanged vertically with the help of inextensible strings and ideal spring Initially the system was in equilibrium At any instant lowermost string is cut then acceleration of block B just after cutting the string is uyu www 888 1 g 1 10 00 2 4 3 4 Zero 164

A varying horizontal force Fat acts on a block of mass m kept on a smooth horizontal surface An identical block is kept on the first block The coefficient of friction between the blocks is u The time after which the relative sliding between the blocks prevails is 2mg 1 2 3 2 mg umg

During a heavy rain hailstones of average size 10 cm in diameter fall with an average speed of 20 m s Suppose 2000 hailstones strike every square meter of a 10 mx 10 m roof perpendicularly in one second and assume that the hailstones do not rebound Calculate the average force exerted by the falling hailstones on the roof Density of a hailstone is 900 kg m

139 A 60 kg man stands on a spring balance in a lift At some instant he finds that the reading on the scale has changed from 60kg to 50 kg for a while and then comes back to the original mark What is his conclusion 1 The lift was in constant motion upwards 2 The lift was in constant motion downwards 3 The lift while in motion downward suddenly stopped 4 The lift while in motion unward suddenly stonned B directly 1 Directl 2 Head 5 3 Head 31 4 The trip 144 A force F

8 Two persons each of mass m are standing at the two extremes of a railroad car of mass M resting on a smooth track figure 9 E10 The person on left jumps to the left with a horizontal speed u with respect to the state of the car before the jump Thereafter the other person jumps to the right again with the same horizontal speed u with respect to the state of the car before his jump Find the velocity of the car after both the persons have jumped off