Newton's law of motion Questions and Answers

A block of mass 8 kg is placed on a rough inclined plane and subjected to a force of 30 N directed up the plane as shown in the figure If the inclination of the plane is 60 and the coefficient of static friction between the block and the plane is 0 4 then total contact force exerted by the block on the plane can be directed along A 60 B F 30 N C E D 4

A 4 60 kg object is attached to a vertical rod by two strings as shown in the figure below The object rotates in a horizontal circle at constant speed 7 20 m s 3 00 m 2 00 m IN 2 00 m a Find the tension in the upper string D Find the tension in the lower string N

2 16 A body is moving down a long inclined plane of angle of inclination 0 The coefficient of friction between the body and the plane varies as 0 1 x where x is the distance moved down the plane The body will have the maximum velocity when it has travelled a distance x given by B x 5 tan 0 A x A x 10 tan 0 C 2 cot 0 D x 10 cot A

An object has a velocity v 21 4 m s at time t 0 s It undergoes a constant acceleration a 1 3 m s for 4 s Then i Find the co ordinates of the object if it is at origin at t 0 ii Find the magnitude of its velocity at the end of 4 s

2 2A cart of mass M has a block of mass m in contact with it as shown in the figure 2 133 The coefficient of friction between the block and the cart is u What is the minimum acceleration of he the cart so that the block m does not fall A g C g a O M O Figure 2 133 B g u D m Mug m 2 bold er s

WI 2 4 A ball is dropped vertically from height d above the ground B It hits the ground and bounces up vertically to a height d 2 Neglecting subsequent motion and air resistance its velocity v varies with height h above the ground as on A B C D A que 200 C d d gains B V D V Smal2000 180 vi Saia Diw un kalky 2455 6 0 2 th is be re g

A block of mass 3 kg rests on a horizontal frictionless XY plane What would be the acceleration of the block if it is subjected to two forces as shown in figure 10 N 60 AY L SN X a 2 5 ms 2 b 5 ms along Y axis c 10 ms 2 along X axis d 15 ms 2 along Y axis

A block of mass 8 kg is placed on rough inclined plane and subjecte force of 30 N directed up the plane shown in the figure If the inclinati the plane is 60 and the coefficien static friction between the block a plane is 0 4 then total contact for exerted by the block on the plane directed along

2 A A block of mass 8 kg is placed on a rough inclined plane and subjected to a force of 30 N directed up the plane as shown in the figure If the inclination of the plane is 60 and the coefficient of static friction between the block and the plane is 0 4 then total contact force exerted by the block on the plane can be directed along 60 O English En B Review F 30 N E D

A uniform rod of mass Mand length hinged at one end is held in equilibrium by applying a constant force Fat other end as shown in figure The system is in vertical plane Force exerted by hinge on the rod is F

A chain has five rings The mass of each ring is 0 1 kg This chain is pulled upwards by a froce F producing an acceleration of 2 50 m sec in the chain Then the force of action reaction on the joint of second and third ring from the top is F m m j TA 2 5m s 0 2 2m 3m ysi 3 S P 917439747061 as5716009 gmail com

Three blocks of masses m m and 2m are connected as shown in figure All the surfaces are frictionless and the pulley and strings are light If m 5 kg then tension in string connected to heavier block in N is g 10 m s 2m a T m m

respectively Two blocks A and B of masses 3 m and m are connected by a massless and inextensible string The whole system is suspended by a massless spring as shown in figure The magnitudes of acceleration of A an B immediately after the string is cut are respectively mo A 3m

282 A car start from rest to cover distance X The coefficient of kinetic friction between road and tyre is The minimum time in which the car can cover the distance x is proportional to 1 Ju 2 slear 3 3 Dago E 0800 A dom sluoria molinu 107 TBS sonol istiqaines holls1916006 slepos

4 Both 1 3 A 5000 kg rocket is set for vertical firing The exhaust speed is 800 ms 1 To give an initial upward acceleration of 20 ms 2 the amount of gas ejected per second to supply the needed thrust will be g 10 ms 1 185 5 kg s 1 2 187 5 kg s 1 3 127 5 kg s 1 3 29

34 For the equilibrium condition shown the cords are strong enough to withstand a maximum tension 100 N The largest value of W in newton that can be suspended is Wo Find Wo 5 toxy TWD x 3 5 100x4 5 10 20 10 4 5 5 53 53 OW 10 h st

Two blocks A and B of masses 3 kg and 2 kg respectively are in contact on a frictionless surface as shown If a force of 10 N is applied on 3 kg block then contact force between A and B is 10 N 3 kg 2 kg O 6N O4N 10 N

A snow load transfers the forces shown to the upper joints of a Pratt roof truss Neglect any horizontal reactions at the supports and solve for the forces in all members 1 kN Ans AB DE BC CD 3 35 kN C AH EF 3 kN T BH DF 1 kN C CF CH 1 414 kN T FG GH 2 kN T 1kN 2 m 1 kN B H 2m 2 m 1 kN D G 2m F 2 m 1 kN E

0 In case if no response is typed selected Two blocks having same mass are placed on rough incline plane and the coefficient of friction between A and incline is B and incline is 2 As the inclination of the plane with respect to horizontal increases Choose the correct a 3 e there is no contact force between block A and B as 0 30 there is no contact force between blocks A and B as 0 45 both the blocks have same accelerations 1 Hitt

NEET Ar 26 Two identical springs initially relaxed have the same force constant 73 5 N m 1 The distance through which block descends in three cases shown in Figure 1 Figure 2 and Figure 3 in equilibrium are g 9 8 ms 2 000000000 000000000 5 kg Figure 1 1 2 1 3 3 2 1 1 3 m m m eeeeeeeeee 5 kg Figure 2 2 4 1 4 m 1 1 1 m m m 3 3 E eeeeeeeee 5 kg Figure 3 m 2 m

e 4 102 A projectile is fired with a speed u at an angle 0 above a horizontal field The coefficient of restitution of collision between the projectile and the field is e How far from the starting point does the projectile makes its second collision with the field Ans 1 e u sin 20

Question 17 Two bodies of masses 4 kg and 5 kg are acted upon by the same force If theacceleration of lighter body is 2 m s the acceleration of heavier body is a 1 m s b 1 2 m s c 1 6 m s

A system consists of three masses m m2 and m3 connected by a string passing over a pulley P The mass m hangs freely and m2 and m3 are on a rough horizontal table the coefficient of friction The pulley is frictionless and of negligible mass The downward acceleration of mass m is Assume m m m3 m M M3 P 1 g 1 gu 9 2 2g 3

2 The velocity time relation of an electron starting from rest is given by v kt where k 2 m s The distance travelled in 3 sec is uch safar farmharen fa gr 2 m s 3 1 9m 2 16m 3 27m 4 36 v kt k

1 A uniform rod of mass m is at rest on a vertical and rough horizontal surface 0 5 as shown in the figure The frictional force acting on it is 3 2 mg 2 3 LATS Liss mg 3 wate 60 2 4 H 2mg 3 60 mg 2 mg H mg 2 2 ny 3 2mg

Question His bernd 92 A boat of mass Mmoving with the help of an ideal string whic h is being pulled with 5 m s as shown in figure A Constant resistive force R is appli ed by the water opposite to the direction

5 In the figure shown all the three bodies 1 2 3 can nove If acceleration of body 1 w r t 2 is a 6m s and acceleration of 3 w r t ground is a 4m s then magnitude of acceleration wedge 2 w r t ground is a 2 m s c 0 4 m s b 0 8 m s d 1 m s a Sunuc

An Australian emu is running due north in a straight line at a speed of 13 0 m s and slows down to a speed of 10 1 m s in 2 60 s a What is the magnitude and direction of the bird s acceleration b Assuming that the acceleration remains the same what is the bird s velocity after an additional 1 20 s has elapsed

2 Given Initial Velocity Final No change in Momentom Area Under f vs t graph gives change momentum which is Zero in this in Case Area must below 2x under graph Above t axis be equal to avea under graph t axis 1 2 2 2 2 2 2x x2 x 2 x 2

An inclined plane is located at angle a 53 to the horizontal There is a hole at point B in inclined plane as hown in the figure A particle is projected along the plane with speed vo at an angle 37 to the orizontal in such a way so that it get into the hole Neglect any type of friction Find the speed vo in m s if 1 m 1 8m and 5 2 25 Vo l 9 1 g 10 m s2

A thin plate with right angled triangular shape is supported by three cables as shown in Figure 2 If the mass of the plate is 95kg determine the tension in three cables 25 1 8m Figure 2 25 M 1 8 m Vertical Cable C

HYSICS sessment Practice Sheet ctric field lines Electric flux Electric dipole Dipole in a 5 The variation of electric field between the two charges q and q2 along the line joining the charges is plotted against distance from q taking rightward direction of electric field as positive as shown in the figure Then the correct statement is 92 r 1 q and q are positive and lq 1 19 1 91 92 2 q and q are positive and 19 1 19 1 92 3 q is positive and q2 is negative 19 1 19 1 92 4 q is negative and q2 is positive q 1 19 1 91 q The magnitude of dipole moment of the following system is

JMS 2017 R 3 9 Q b ons 5 In a cer along the z direction througho magnitude of electric field is however not constant but increases uniformly along the positive z direction at the rate of 10 NC m The force experienced by the system having a total dipole moment equal to 107Cm in the AIIMS 2015 negative z direction is a 10 2 N b 10 2 N c 10 N d 10 N Three charged particles are collinear and are in equilibrium then AIIMS 2014 a all the charged particles have the same polarity b the equilibrium is unstable c all the charged particles cannot have the same polarity d Both b and c are correct a c 12 TH p x T C 50 C 100US

A boy throws a ball vertically upwards then 1 work is done by the boy throughout the motion of the ball 2 work is done by the boy only during upward motion of the ball 3 work is done by the boy only at the moment he throws the ball 4 work done by boy on it is zero

In the figure shown masses of A is 5 Kg All pulleys and strings are ideal then 0 Clear Response If acceleration of A is 1 m s upwards acceleration of B is 3 m s downwards If acceleration of A is 3 m s upwards acceleration of B is 1 m s downwards If mass of B is 20 kg then acceleration of B is g 184 downwards If mass of B is 20 kg then acceleration of A

In the figure shown the man pulls the strings with velocity u from both ends and the block of mass M always remains horizontal Then P M Pa Velocity of block of mass M is 3u 4 Velocity of pulley P is 2u Velocity of pulley P is 3u 4 Clear Response Velocity of pulley P3 is u 2

If Newton s Third Law is true then why do chairs break when a heavy boulder is kept on it Because the force the boulder applies should be balanced by the force applied by the chair Please answer

mass one is Consider the arrangement shown in figure Two identical the other is movable are placed on the same surface smooth Assume all ideal conditions of mass m is attached to the string and a force F 2mg is applied at the free end Wedge Wedge A moveable A f X4 1 The acceleration of the wedge A is 2m a zero b M The acceleration of the hanging block m is c m M c 0013 8 B 771 a g b 2g The force exerted by the hinge on pulley of the wedge is a 2 2 2 mg b 2 2 2 mg c 2 2 mg FLITE SERIES for Sri Ch d d m 2M 8 4 d 2 2 mg

A bus starts from rest moving with an acceleration of 2m s A cyclist 96 m behind the bus starts simultaneously towards the bus at 20m s After what time will he be able to overtake the bus 1 8 2 10 s 3 12 s 4 1 s

Body A is placed on frictionless wedge making an angle 0 with the horizon The horizontal acceleration towards left to be imparted to the wedge for the body A to freely fall vertically is A g sine C g tane B g cose Dig cote

In the winter sport of bobsledding athletes push their sled along a horizontal ice surface and then hop on the sled as it starts to careen down the steeply sloped track In one event the sled reaches a top speed of 9 2 m s before starting down the initial part of the track which is sloped downward at an angle of 9 0 Y Part A What is the sled s speed after it has traveled the firsa Express your answer with the appropriate units

80 Two masses m and Mare attached with strings as sho For the system to be in equilibrium we have 2M a tan 0 1 b tan 0 1 c tan 0 1 d tan 0 1 m 2m M M 2m m 2M 45 m M 45 0

A Cycle Crossing Busses Periodically Between two points X and Y on a straight road consistently buses are departing from Y to X and X to Yat uniform speed every 7 minutes A cyclist riding from X to Yat 10 km hr Every 8 minute a bus overtakes him in his direction of motion and crosses him every 6 minute in opposite direction Find the speed of buses and time between departure of two buses

7 A B 50 N T 1 a 2 5 m s a 2 5 m s 2 a 5 m s a 2 5 m s 3 a 2 5 m s a 5 m s MA m 10 kg nuine System is initially at rest and friction coefficient between the blocks is 0 5 while the ground surface is smooth The acceleration of two blocks 4 51 A esm

A particle is projected with some velocity u making an angle 60 with horizontal on to an inlcined plane making an angle 30 with horizontal its range on the inclined plane is Pg no 50 1 2u 3g 2 3 21 4u 4 3g Range along Inclined docct for

58 The areas of cross section of two wires of the same material are in the ratio 1 2 and their lengths are in the ratio 2 1 If their ends have the same potential differences then currents through them will be in the ratio of 1 1 2 2 2 1 3 1 4 4 4 1

Answer ately matching the lists based on the information given in the paragraph In the figure shown the masses of each of the pulley disc is m They were at rest All the threads are light and inextensible Now the thread is cut at B Denoting the acceleration of the discs as a a2 a3 a4 respectively match the correct value of acceleration thereafter List I I a II a III az IV a4 P Q R S T U wwwwwww 3 4 List II 0 m s 10 m s 80 9 m s 110 9 m s 4 m s 2 m s A I U II P III T IV Q B I T II P III T IV Q C I U II P III U IV Q D I T II P III U IV Q

marks System shown in the figure is released from rest Which of the following statements is are Magnitude of acceleration of each block is 3 m s Tension in the cord A is 6 5 N 30 Tension in the cord B is 8 N 0 5kg Difference of magnitudes of tensions in both the cord is 1 5 N aise 0 5 kg

Pulleys provide what is called a mechanical advantage If the force required to lift the 100N wight in figure 1 is 100 N then the mechanical advantage is 1 What is the mechanical advantage for figure 2 if the force required to lift the 100 N weight is 50 N 1 2 3 100 N 10 cm 50 N 1 2 E 100 N 10 cm 100 N 02 O There is no mechanical advantage F 50 N 20 cm E 100 N 10 cm 50 N 25 N 40 cm LLLLLLL F 100 N 10 cm 25 N

Choose the correct statement s A Newton s 1st law of motion is applicable only in inertial reference frame A reference frame moving with constant velocity with respect to another reference frame B implies that they both can either be inertial or both non inertial reference frame C For action reaction pair first the action occurs and then reaction takes place D Newton s 3rd law is valid in non inertial frame too