Kinematics Questions and Answers

A hosepipe lying on the ground shoots a stream of water at an angle of 60 with the horizontal with a velocity of 20 m s The height at which the water strikes the wall at a distance of 10 m is g 10 m s O 8 5 m O 12 32 m 15 5 m

c 2 i 1 8 A cricket ball thrown across a field is at heights hi h from the point of projection at times ti t2 and fielder at the same height respectively after the throw The ball is caught by a height as that of projection The time of flight of the ball in this journey is WB JEE 2014 a ht hati hit h t for hyt h t ht hat hyt 2 hat hitz hati d None of these b tol the

A projectile is fired at an angle of 30 to the horizontal such that the vertical component of its initial velocity is 80 ms Its time of flight is T Its velocity at the moment t T 4 has a magnitude of nearly Take g 10 ms and 13 3 6 O O O 200 m s 160 m s 145 m s

are to be sent across the a canon that can hurl packets at a speed of over the hill The canon is located at a hill 1 using 125 ms 1 distance of 800 m from the foot of hill and can be moved on the ground at a speed of 2 ms so that its distance from the hill can be adjusted What is the shortest time in which a packet can reach on the across the hill Take g 10 ms jeongol 1 0 c 35 s 85 A hill is 500 m high Supplies a 10 s b 25 s CC 1 4 3 91 NCERT Exemplar d 45 s adge of horizontal table at a

A projectile is fired from the surface of the earth with a velocity of 5 m s and at an angle 8 with the horizontal Another projectile fired from a planet with a velocity of 3 m s at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth What is the value of the acceleration due to gravity on the planet in m s2 Given g 9 8 m s O 5 9 O O 16 3 110 8

Two second after projection a projectile is travelling in direction inclined at 30 to be horizontal After 1 more second it is travelling horizontally Then Take g 10 ms 2 a the velocity of projection is 20 3 ms 1 b the angle of projection is 30 with horizontal c Both a and b are correct d Both a and b are wrong 88 a Co 2X4 4 angle of 30 to the horizonta

A stone is projected with a velocity v making an angle 8 with the horizontal Its kinetic energy at the highest point is half of its initial K E What is the angle of projection O O 30 60 O 75

The horizontal and vertical displacements of a projectile at time tare x 36t and y 481 4 9t respectively where x and y are in metre and t is in second Initial velocity of the projectile in m s is O 15 O O O 30 45

A projectile is given an initial velocity of i 2 m s where is along the ground and j is along the vertical If 8 10 m s the equation of its trajectory is O OO O yx s y 2x 5x 4y 2x 5x 4y 2x 25x4

Figure below is the velocity graph of a toy train Its position at t 0 s is 2 2 0 m Figure 1 Figure V m s 0 1 2 N 4 6 8 10 1 of 1 t s What is the train s acceleration at t 3 0 s7 Express your answer to two significant figures and include the appropriate units az 1 00 Correct Part B Previous Answers What is the train s position at t 6 0 s Express your answer to two significant figures and include the appropriate units Az 16 Submit HA m Previous Answers Request Answer Incorrect Try Again 3 attempts remaining Revi

released from rest from a height h on two ramps of different inclinations as shown in the figure Which of the following is true for this scenario Assume all surfaces to be smooth A h OB Leave a comment Science basic concept focus Q 5 Anonymous Quiz 932 11 37 AM 37 a Both A and B reach the bottom at the same time 32 b A reaches the bottom before B X 19 c A reaches the bottom before B D

A stone of a mass 100 gram is projected with an initial velocity at some angle with the horizontal A small piece of mass 10 gram separates from the stone before the stone reaches the maximum height Then this small piece will O O O fall to the ground vertically lag behind the parent stone the maximum height and then fall vertically fly side by with the parent stone along a prabolic path reach

125 m b 3 A grasshopper can jump maximum distance 1 6 m How far can it go in 10 s a 5 2 m c 20 2 m d 40 2 m b 10 2 m c 20 2 m Il rolls off top of a stair way with a horizontal h metres high and

particle explodes into two comes to Mest and falls ander part strikes on ground strike on ground 0 Velocity of second paut just after explaich At the most equal parts 82 At point One of them gravity 10 where will the second part ubs where will com

3 450 ms Duubi dasinos ou 21 A train of 150 m length is going towards North direction at a speed of 10 ms 1 A parrot flies at a speed of 5 ms 1 towards south direction parallel to the railway track The time taken by the parrot to cross the train is 1 12 second 3 15 second 2 8 second 10 second

14 A juggler maintains four balls in motion making each of them to rise a height of 20m from his hand What time interval should he maintain between throws of saccessive balls 1 3s 2 S 1s 2002 0 Two particles A and B are thrown in directions as 4 2s

A football of mass 0 42 kg is passed with a velocity of 25 m s due south A defending player lunges at the ball and w deflects it so that the new velocity is 20 m s 36 9 west of south figure If the player is in contact with the ball for 0 05 s what is the magnitude of the average force he exerts a 63 N c 75 N 20 36 9 b 126 N d 105 N

1 74 A point moves in the plane xy according to the law x a sin oot y a a cos oot where a and o are positive constants Find a The distance s traversed by the point during the time T b The angle between the point s velocity and acceleration vectors Ans a gor b TT

3 6 5 hour 4 20 A police jeep is chasing a thief with velocity of 45 km hr who is moving in another jeep moving with velocity 153 km hr 1 Police fires a bullet with muzzle velocity of 180 ms 1 The velocity with which the bullet appears to strike the jeep of the thief to the thief is 150 ms 1 3 450 ms 1 2 27 ms 1 4 250 ms 1

19 A motor boat covers a given distance in 6 hour moving downstream on a river It covers the same distance in 10 hour moving upstream The time it takes to cover the same distance in still water is 1 9 5 hour 3 6 5 hour 4 8 hour 20 A police jeep is chasing a thief with velocity of 45 1257 27 5 hour

What is the minimum value of force F that can be applied to the bar C to keep bodies A and B stationary relative to the bar C The masses of the bodies A and B are equal and the coefficientof friction between the bar and the bodies is equal to p The masses of the pulley and the threads are negligible the friction in the pulley is absent There is no friction between C and the floor P m A M C m B

3 Z kt c 2 4 kt 2 ct A thief is running away on a straight road in a jeep moving with a speed of 9m s A policeman chases him on a motor cycle moving at a speed of 10m s and the instantaneous separation of the jeep from the motor cycle is 100 m how long will it take for the policeman to catch the thief 1 1s 2 19s 100s 3 90s If a particle travels distance s S and s3 taking realme Shot by Souradeep Manna

67 A particle is projected with a velocity of 30 ms at an 3 1 After 1 S the particle is 4 4 4 moving at an angle 0 to the horizontal where tan 0 will be equal to Take g 10 ms 2 a 1 b 2 c angle of 00 tan m 2 d 3 25x2 the ground with a velocity

stant The velocity of 1 kt ct 2 1 1 2 ct ght road in a jeep oliceman chases speed of 10m s of the jeep from g will it take for S and s taking stangon Fi 6 m s 1 0 2 2 3 0 0 4 m s 4 0 0 2 m s The acceleration time graph of a particle moving along straight line is as shown in the figure What is the velocity of the particle at t 8 sec if initial velocity of particle is 3 m s a m s 1 4 m s 2 5 m s 3 1 m s 0 1 4 8 t s roalmo

1 A ball is projected upwards from the top of a tower with velocity 25 ms 1 making an angle of 30 with the horizontal If the height of the tower is 70 m after what time from the instant of throwing will the ball reach the ground Take g 10 ms 2 a 2 s b 5 s e 7 s d 9 s

Three particles are projected from ground from origin All particles reach same maximum height x is horizontal and y is vertical List I P Time of flight is least Q Initial vertical component of velocity is greatest R Horizontal component of velocity is greatest S Launch speed is least A C P 3 Q 1 R 2 S 4 List II 1 2 3 4 A C Same for all

77 A ground to ground projectile is at point A at t point B at t 5T 6 difference in heights between points A and B is a 972 972 12 6 c 972 18 and reaches the ground at t t b d 972 24 T is at 3 T The

A projectile is thrown from a point O It moves in such a way that its distance from O is always increasing Find the maximum value of tan where 8 is the angle above the horizontal with which the projectile could have been thrown you can ignore air resistance

8 A particle A is dropped from a height and another particle B is thrown in horizontal direction with speed of 5 m s from the same height The correct statement is a both particles will reach at ground simultaneously b both particles will reach at ground with same speed c particle A will reach at ground first with respect to particle B d particle B will reach at ground first with respect to particle A

9 The deceleration experienced by a moving motorboat after dv KV where K is its engine is cut off is given by dt 0 constant If Vo is the magnitude of the velocity at cut off the magnitude of the velocity at a time t after the cut off is a b Voe kt 0 Vo 2V Kt 1 V d V

A hall has the dimensions 10 mx10m x 10 m A fly starting at one corner ends up at a diagonally opposite corner The magnitude of its displacement is nearly 1 5 3 m 101 5 2 10 3 m 4 30 3 m

A man holds an umbrella at 30 with the vertical to keep himself dry He then runs at a speed of 10 ms and finds the rain drops to be hitting vertically Speed of the rain drops w r t the running man and w r t earth are 20ms 10ms 1 10ms 20 3ms 1

15 Rain is falling vertically with velocity 10 m s and a man is moving horizontally with velocity 6 m s The angle with which umbrella should be hold with vertical by man to avoid getting wet is 2 2 tan 1 5 M 5 tan tan tan 4 tan 1 3

An object is projected with a velocity of 20 m s making an angle of 45 with horizontal The equation for the trajectory is h Ax Bx where h is height x is horizontal distance A and B are constants The ratio A B is 1 1 5 2 5 1 3 1 40 4 40 1

A man in a boat starts from a point A and wants to reach a point C on the other bank of a river of width b The point C is at distance a downstream from a point B which is directly opposite to the point A The water current velocity Uw is uniform everywhere Find the minimum speed of the boat relative to the water current and corresponding direction in which the boat must be steered B 90

SAMPLE PROBLEM 2 9 A body is dropped from rest and falls freely Determine the position and velocity of the body after 1 0 2 0 3 0 and 4 0 s have elapsed Solution We choose the starting point as the origin so that Yo 0 We know the initial speed zero and the acceleration and we are given the time To find the position we use Eq 2 30 with Yo 0 and Voy 0 y gt y yo Voyt 1 2 a t y 0 Voy 0 Substitute for g 9 8 m s and for t 1 0 s calculate y Substitute for g 9 8 m s and for t 2 0 s calculate y Substitute for g 9 8 m s and for t 3 0 s calculate y Substitute for g 9 8 m s and for t 4 0 s calculate y To find the velocity we use Eq 2 29 again with voy v gt m s s Substitute for g 9 8 m s and for t 1 0 s calculate v Substitute for g 9 8 m s and for t 2 0 s calculate v Substitute for g 9 8 m s and for t 3 0 s calculate vy Substitute for g 9 8 m s and for t 4 0 s calculate v Result For t 1 0 s y For t 2 0 s y For t 2 0 s y m and Vy m and Vy m and Vy m s m s m s 0 m s

A car starts from rest at 5 00 p m The distances covered by the car at various instants of time are recorded as follows 5 00 5 30 30 O 6 00 60 Time pm Distance km a Draw a distance time graph b What distance was covered by the car at 6 15 pm 6 30 90 7 00 120 7 30 150

Two blocks of masses 1 kg and 2 kg are connected with massless spring as shown If the acceleration of 1 kg block is 1 m s towards right then the acceleration of 2 kg block is NCERT Pg 94 1 ka 2 kg 5 N

18 Tick the correct answers from answer grid Motion with uniform velocity Angle between the instantaneous displacement and acceleration during the retarded motion Velocity time graph of uniform motion c zero Area under velocity time graph for a given motion d 180 Slope of velocity time parallel to time axis distance covered during that motion C zero 180 U 0 0 5 point Average speed average velocity

Two springs with negligible masses and force constant of k 200 Nm 1 and k 160 Nm 1 are attached to the block of mass m 10 kg as shown in the figure Initially the block is at rest at the equilibrium position in which both springs are neither stretched nor compressed At time t 0 a sharp impulse of 50 Ns is given the block with a hammer x is compression in left spring period of oscillation for the mass m is S k vooroo m maximum velocity of the mass m during its oscillation is 5 ms 1 k 0000 00 ratio of Potential energy of left spring U and Kinetic energy of block K varies as UK frictionless 20x 25 36x2

A ball is launched straight downwards at 17 m s from the top of a building which is 117 meters height above the ground What is the velocity of the object in m s just as it reaches the ground If in the negative y direction indicate so with a negative sign

The speed time graph of a particle moving along a straight line is shown in figure If distance in metre traversed by the particle in the time interval t 2 s to t 6 s is S then find the S 10 Speed m s value of 20 5 10 Answer 00 01 02 03 04 05 06 07 08 09 t s

A motorboat going downstream overcame a raft at a point A at t 0 After 30 min engine of boat shutdown due to some fault The man on the boat repairs the engine and it takes 30 min The boats starts and turn back After sometime it passes the raft at a distance km from the 21 2 point A Find the flow velocity of stream in km h Assume velocity of motorboat constant with respect to river flow

Buses ply from city A to city B at regular interval of 15 minutes Every bus from A to B moves with consta speed 40 km h A car X moving from city B to city A meets buses at an interval of 5 minutes The speed the car X is n 10 km h Find the value of n 17

Analyse the following 1 If two particles are moving towards each other under the action of mutual attractive force then they will collide at the centre of mass of the system i If a bomb at rest explodes then fragments fly off in different directions But centre of mass of the system remains at rest iii When a shell projected from ground explodes in mid air the fragment fly off in different directions describing their own parabolic paths But the centre of mass of all fragments would still continue to move along the same parabolic path along which it was moving before explosion iv Consider a system of two particles having masses m and m If m is pushed towards the centre of mass of the system through a distance d then to keep the centre of mass at the same position m has to be moved through a distance m m d v A uniform stick having very large height is placed vertically on the surface of earth Its centre of mass coincides with centre of gravity 1 i ii and iii are correct 3 iv and v are correct 2 i ii and iv are correct 4 i ii iii and iv are correct

14 A scooterist is moving on a straight road with speed 10 ms 1 A bus ahead of scooterst by 32 m starts from rest with an acceleration 1 ms 2 If both are moving in the same direction then the time afte which scooter overtakes the bus is x 10 4 1 16 s 2 4 s 3 8 s s at Lat It connot overtake the bus lot

tan 35 35 7 A motorboat is racing towards north at 25 km h and the water current in that region is 10 km h in the direction of 60 east of south The resultant velocity of the boat is a 11 km h 1 c 33 km h b 22 km h d 44 km h B Which of the following in dil wi a J c 13 If t

ball A is thrown vertically upward with a speed of 19 6m s from the top edge of a high buildin as it passes the edge on th eway down a second ball B is thrown downward at 19 6 m s and time t is w hat

Two buses A and B are travelling along a straight line in the same direction with speeds 50 kmph and 30 kmph The velocity of A relative to B is 1 20 kmph 2 30 kmph 3 60 kmph 4 50 kmph

For any value of M 2 Two blocks m and m are in equilibrium S is a string and S is a spring of spring constant k Immediately after the string S is cut M F m2 9 1 the acceleration of m is 2 the acceleration of m is zero m g m 3 the acceleration of m is m m 4 the acceleration of m is g m m g m m ELITE SERIES for Sri Chaitanya Jr ICON Students m S an 9 m S m 149