Kinematics Questions and Answers

8 At a particular instant a particle moving with a constant velocity is approaching a fixed point with a velocity u 3 m s and after a time interval At 6 s the particle passes the position closest to the fixed point with a velocity v 5 m s Find the closest distance between the fixed point and the particle

A particle of mass m moves on the x axis as follows It starts form rest at t 0 from the point x 0 and comes to rest at the point x 1 No other information is available about its motion at intermediate time 0 t 1 if a denotes the instantaneous acceleration of the particle then IIT JEE 1993 Choose only 1 answer A a cannot remain positive for all t in the interval 0 t 1 B la cannot exceed 2 at any point in its path C a must be 4 at some point or points in its path Your Answer a must change sign during the motion

Q11 A baseball player hits back the ball straight in the direction of the bowler without changing its initial speed of 12 ms If the mass of the ball is 0 15 kg Find the impulse imparted to the ball Consider the ball in linear motion a 1 2 Ns b 2 4 Ns c 3 6 Ns d 4 8 Ns

a 38 A system is shown in the figure A man standing on the block is pulling the rope Velocity of the point of string in contact with the hand of the man is 2m s downwards The velocity of the block will be assume that the block does not rotate sem sasig baritoni GA IS c 1 2 m s d 1 m s a 3 m s b 2 m s

grou 3 The Ekstreme Tower at Enchanted Kingdom amusement parkis 175 feet tall How long does it take for the ride to reach the ground Conversion 1m 3 28ft

A stone released with zero velocity from the top of a tower reaches the ground in 4 sec The height of the tower is g 10m s 1 20m 4 160m O O 2 O 3 2 40m 3 80m 5

Q4 A lift of mass 1000 kg is moving upwards with an acceleration of 1 m s The tension developed in the string which is connected to lift is g 9 8 m s CBSE AIPMT 2002 a 9800 N b 10800 N c 11000 N d 10000 N

Check up the only correct statement from the following 1 Abody has a constant velocity and still it can have a varying speed 2 A body has a constant speed but it can have a varying velocity 3 Abody having constant speed cannot have any acceleration 4 None of the above are correct 01 02 03 O 4

A block slides down on an icy hill of height h as shown in Fig and stops after covering a distance CB The distance AB is equal to S The coefficient of friction u between the block and ice surface inclined and horizontal is h S h S Fig 8 178 Correct Answer Your Answer

small block is projected with a speed vo on a fixed horizontal track which turns into a semi circle vertical of radius R The minimum value of to so hat the body will hit the point A after leaving the track at its highest point is 0 min gR The arrangement is shown in the figure given that the traight part is rough and the curved path is smooth The coefficient of friction is p 0 25 Find o 2R

Which one out of the following statements is false 1 A body can have zero velocity and still be accelerated 2 A body can have a constant velocity and still have a varying speed 3 A body can have a constant speed and still have a varying velocity 4 The direction of the velocity of a body can change when its acceleration is constant 4

From a building two balls A and B are thrown with same speed such that A is thrown upwards and B downwards both vertically Ifv and v are their respective speeds on reaching the ground then 1 VB VAL 3 VA VB 01 2 VA VB 4 their speeds depend on their masses

Two balls of same mass are projected as shown by compressing the springs of different force constants K and K by equal magnitude The first ball is projected upwards along smooth wall and the other on the rough horizontal floor with coefficient of friction If the first ball goes up by height h then the distance covered by the second ball will be T Cre ie K mm

A car covers the first half of the distance between two places at 40km h and other half at 60km h The average speed of the car is 1 40km h 2 48km h O 2 03 DI 3 50km h 4 60km h

B 16 A stone projected from edge A of a high cliff strikes the ground at point C moving almost vertically Reason for this strange behavior is air resistance that is proportional to the speed of the stone The points A and B on the trajectory are in the same horizontal level Time taken by the stone in its upward and downward motions above the level AB differ by At and moduli of vertical component of velocities at points A and B differ by Au Horizontal component of velocity at point A is u and horizontal displacement of the stone from A to C is R Denoting acceleration due to gravity by g find suitable expression for the rimum hoight of the ato above the horizontal levral AR

a between diametrically opposite points is half of the induced e m f d all points on the surface are at the same potential 2 A particle is projected vertically upwards in the absence of air resistance with a velocity u from a point O When it returns to the point of projection a its average velocity is zero b its displacement is zero c its average speed is u 2 d its average speed is u Two points charges Q and O are plan

A boat on one bank of the river wants to reach other bank of river flowing with speed vo Speed of boat in still wat is also vo Boat moves in such a way that its distance from a fixed point P remains constant equal to 2d If time tak to cross the river is in x 1 then value of x is Vo Boat

A plane starts at rest on a straight runway For the first 30 s the plane s acceleration a is giver as a function of time by the equation a B where B 1 90 m s and 1 is in seconds What is the plane s speed at t 30 s A 10 m s B 30 m s C 100 m s D 150 m s E 300 m s Usac

A uniform thin rod AB kept in horizontal plane of length L and mass m is undergoing fixed axis rotation about an axis passing through end A and perpendicular to the horizontal plane as shown The kinetic energy of section AP of rod is equal to kinetic energy of section BP of rod at any instant Then the ratio of length AP and length AB that is AP is equal to AB O 72 A P m L O 21 3 B

38 A point object is moving with speed 4 cm s in front of a combination of two plane mirrors see figure Velocity of image of the object formed by mirror M relative to image formed by mirror M is Po 4 cm s w 30 M AY X M 7 1 2 1 31 cm s 2 2 31 23 cm s 3 2 1 31 cm s 4 2 31 1 cm s

A particle moves in the xy plane with only an x component of acceleration of 2 ms 2 The particle starts 0 with an initial velocity having an x component of 8 ms 1 and y component of 15 ms Velocity of particle after time t is from the origin at t A 8 2t i 15 m s 1 C 2ti 15 j B zero D directed along z axis

A cracker is thrown into air with a velocity of 10 m sec at an angle of 45 with the vertical When it is at a height of 0 5 m from the ground it explodes into a number of pieces which follow different paths What is the velocity of centre of mass when it is at a height of 1m from ground 1 4 5 m s 2 2 5 m s 3 5 4 m s 4 10 m s

cannon installed at the top of a hill can fire shells in all directions here is an enemy bunker at an angle of elevation and a distance d om the cannon All the shells fired explode in air in time T before they each the bunker At what angle to the horizontal should a shell be fired with a speed u to explode closest to the bunker Acceleration due to ravity is g

When no external force is acting on a particle the centre of mass of the system Remains at rest Moves with constant velocity only Moves with constant velocity or will be at rest Move with variable velocity

A ball is released from the top of tower of height h metre It takes T second to reach the ground What is the position in m from the ground of the ball in T 3 second 1 h 7h 2 Th 3 8h 4 17h 18

Q18 Two particles A and B are connected by a rigid rod AB The rod slides along perpendicular rails as shown here The velocity of A to the right is 10 m s What is the velocity of B when angle a 60 CBSE AIPMT 1998

A boy of mass M stands at the edge of a circular platform of radius R capable of rotating freely about its axis The moment of inertia of the platform about the axis is I The system is at rest A friend of the boy throws a ball of mass m with a velocity v horizontally The boy on the platform catches it when it passes tangentially to the platform Find the angular velocity of the system after the boy catches the ball O O O O mv R I mR mvR 1 MR mVR M m R mvR 1 M m R

Two similar cannon simultaneously fires two identical cannon balls at target 1 and 2 as shown in the figure If the cannon balls have identical initial speeds which of the following statements is true 2 1 Target 2 is hit before target 1 2 Target 1 is hit before target 2 3 Both are hit at the same time 4 information is insufficient

Q21 A particle is projected with a velocity v such that its range on the horizontal plane is twice the greatest height attained by it The range of the projectile is where g is acceleration due to gravity a b c d 4u 59 49 5v 59

6 A body of mass 2kg having an initial velocity u m s is undergoing the motion as given in the F t curve Calculate its velocity in m s after 3 second F is along the line of u F N 1 u 6 3 u 1 5 4 2 t sec 2 u 3 4 u 1 33

A body of mass m 102 kg is moving in medium and experience a frictional force F kv its initial speed is vo 10 ms After 10s it 1 kinetic energy ismv2 then value of k will be 1 10 kg m s 2 10 kg m 3 10 kg s 4 10 kg m

A particle starts with angular acceleration 2 rad sec It moves 100 rad in a random interval of 5 sec Find out the time at which random intervel no bosga starts 1 7 5 sec 2 4 5 sec 3 5 sec to 4 6 sec

A particle moves so that its position vector is given by r coswt X sin ot y where w is a constant Which of the following is true NEET 2016 1 Velocity is perpendicular tor and acceleration is directed away from the origin 2 Velocity and acceleration both perpendicular to r are 3 Velocity and acceleration both are parallel to r 4 Velocity is perpendicular tor and acceleration is directed towards the origin

A particle is moves in a straight line with retardation proportional to its displacement Its loss in kinetic energy for any displacement a would be proportional to ICH P AT x 23 Your Answer

A truck travelling due north at 50 km h turns west and travels at same speed What is the change in velocity A50 km hN W B D 50 2 km hN W 50 km hS W 50 2 km hS W

A particle is moving in X Y plane such that vx 4 4t and v 4t t in seocnd and v v in m s If the initial position of particle is 1 2 m Then the equation of trajectory is y 1 y 4x 2 y 2x Y 2 3 x 4 None of these

Which statement can be impossible cases in one two dimensional motion AA body has zero velocity and still be accelerating B The velocity of an object direction when is constant reverses acceleration An object be increasing in speed as its acceleration decreases DNone of these Kone

If magnitude of change in velocity of particle projected from ground till it lands on ground as shown in figure is 2m s find maximum height of the projectile g acceleration due to gravity 1 1 g E 2 3 m q 1 2 m 4g 4 1 20 3

RR A B B P A B Fig 1 10 Subtraction of vector B from vector A How do we subtract one vector from another If you recall that the difference of two vectors A B is actually equal to A B then you can adopt the same method as for addition of two vectors It is explained in Fig 1 10 Draw vector B from the tip of A Join the tail of A with the tip of B The resulting vector is the difference A B You may now like to check your progress

A car is moving along a straight horizontal road with a speed v If the coefficient of friction between tyres and the road is u The shortest distance in which the car can be stopped is 1 2 g ve Vo ILG 3 2 4 g 2v g

4 none of these A farmer has to go 500 m due north 400 m due east and 200 m due south to reach his field If he takes 20 min to reach the field what is the average velocity of farmer during the walk 1 35 m min 2 45 m min 3 25 m min 4 55 m min

A block of mass 10 Kg is held stationary on the smooth and fixed inclined plane of inclination of 60 with the help of an ideal string as shown in figure The magnitude of normal reaction exerted by a wedge on the block is g 10 m s B 50 3 N 50 N 100 N Correct Answer Your Answer

F N 6 0 4 0 2 04 0 0 2 0 3 0 4 0 A 4 0 N s B 8 5 N s C 13 N s D 25 Nes 5 0 6 0 s 7 A 300 g cart with a force sensor attached starts at rest on a track The force sensor exerts a force on the cart to speed it up The graph above shows the force F exerted by the sensor on the cart as a function of time t The change in the cart s momentum during the time interval shown is most nearly D

Two cars are moving in same direction with same speed 30 km hr they are separated by a distance of 5km speed of car moving in opposite directions if it meets these two cars at an interval of 14 minutes will be Ans given 45km hr

78 A body is thrown with velocity 4i 3j metre per second Its horizontal range and time of flight are 1 2 4 m and 0 6s 2 3 2 m and 0 8 s 3 5 m and 2 s 4 7 m and 1s

covers 74 A body falls freely 36 of the total height in the last second before striking the ground level The height of the tower is c 100 m d 125 m b 75 m a 50 m car whose floor to ceiling distance is

18 A man crosses the river perpendicular to river flow in time t seconds and travels an equal distance down the stream in T seconds The ratio of man s speed in still water to the speed of river water will be t T A T B T 1 T 1 C 1 T 1 T D T t T t

23 Two small balls A B are launched in the same vertical plane simultaneously with same speed of 20 m s at t 0 Ball A has an initial horizontal velocity and ball B has initial velocity at an angle above the line joining A and B as shown If the projectiles collide in mid air at timet A 0 45 100m B 0 60 In the figure shown twn hoate at 20 m s 100 3 m C t 20 20 m s D t 10

22 The acceleration due to gravity on a planet i 1 96 m s If it is safe to jump from a height 3 m on the earth the corresponding height on th planet will be 1 3 m 3 9 m 2 6 m 4 15 m

Depict the shown v x graph in a x graph A C a A B D Vo Xo X