Kinematics Questions and Answers

Q 14 A swimmer wishes to cross a 500m wide river flowing at 5km hr His speed with respect to water is 3 km hr If he heads in the direction making an angle with the flow find the time he takes to cross the river a c cose 10 sine minutes minutes b d 10 sing cose seconds seconds

Can you explain to me as to what is meant by the line tha the component of velocity along the direction of force i s changed This implies that if a force is applied at some angle to the velocity of the body then only the component of velocity along the direction of force is changed The component of velocity normal to the force remains unchanged iii The equation F ma is applicable to a single point portiola Onl

Consider the motion of the tip of the minute hand of a clock In one hour B A The displacement is non zero C The average speed is zero D The distance covered is zero The average velocity is zero Which of the following statement is not true A If displacement covered of a particle is zero then distance covered may or may not be z If the distance covered is zero then the displacement must be zero B C D The numerical value of ratio of displacement to distance is equal to or less than one The numerical value of the ratio of velocity to speed is always less than one

A man starts from point P and goes 20 m due East then 5 m due North then 35 m due West and finally 25 m due South His displacement from point P is 1 25 m at tan 1 West of South 2 85 m in South West 3 25 m at tan 4 15 m at tan 1 West of South 3 West of South

company will receive the maximum monthly income A projectile is launched from a point 40 feet above the ground The height at ground level h in feet after t seconds is given by the function g t 40t 5t2 Find the maximum height of the projectile and the number of seconds will it take to reach the maximum height

A particle of unit mass undergoes one dimensional motion such that its velocity varies according to v x Bx where and n are constants and x is the positi of the particle The acceleration of the particle as a function of x is given by a 28 x 2n 1 b 2n x 4n 1 C 2n x 2n 1 2n82y 4n 1 2n 1

3 You are at the airport A moving sidewalk moves East at 2 5m s with a supermodel just standing on it letting the sidewalk move her As you sit on a bench people watching you observe a dad pushing a child in a stroller walking parallel to the moving sidewalk 1 0m s west A hurried professional is traveling at 5 0m s E total while on the moving sidewalk and has to avoid the 9 year old child walking west at 2 5m s on the floor and headed toward the moving sidewalk What is the velocity of the dad relative to the professional What is the velocity of the supermodel relative to the professional C What is the velocity of the professional as soon as they leave the sidewalk d What is the velocity of the 9 year old relative to you when the 9 year old steps onto the moving sidewalk a b

The force exerted by the floor of an elevator on the foot of a person standing there is more than the weight of person if the elevator is A going up and slowing down C going down and slowing down B going up and speeding up D going down and speeding up

A man wants to reach point B on the opposite bank of a river flowing at a speed u as shown in the figure What minimum speed relative to water should the man have so that he can reach directly to the point B B A B C 2 30 with upstream u 45 u u 45 with downstream 45 with upstream Correct Answer

WTON S LAWS Two masses M and M are connected to the ends of a string passing over a smooth pulley The tension in the string is T and the masses are moving with acceleration a If the masses are interchanged then A both a and I will change B a will change but T will remain unchanged C T will change but a will remain unchanged D none of them will change

08 The elevator shown in figure is descending with an acceleration of 2 ms 2 The mass of the block A 0 5 kg The force exerted by the block A on the block B is A 2 N B 4 N A B 2 ms 2 C 6 N D 8 N

A perfectly reflecting solid hemisphere of radius R is placed in the path of a parallel beam of light aperture If the beam carries an intensity I the force exerted by the beam on the hemisphere is O 2TR 1 C TR 1 C 4 R 1 C TR 1

The driver of a three wheeler moving with a speed of 36 km h sees a child standing in the middle of the road and brings his vehicle to rest in 4s just in time to save the child What is the average retarding force on the vehicle The mass of the three wheeler is 400 kg and the mass of the driver is 65 kg

A lift is accelerated upward Will the apparent weight of a person inside the lift increase decrease or remain the same relative to its real weight If the lift is going with uniform speed then

5 Two men can swim in still water at the rate of 5 km h One swims upstream a distance equal to the width of the river half km and back again The other swim to a point straight across and back again Assuming that the velocity of the river is 3 km h find the difference in times taken by them

A 31 0 cm diameter hollow sphere is suspended by a wire The system requires a torque of 0 264 N m to twist the wire and rotate the sphere 0 795 radians When the torque i removed the system oscillates with a period of 11 seconds What is the mass of the sphere

A particle is moving along straight line whose position x at time t is described by x t t where x is meters and t is in seconds Then the average acceleration from t 2 sec to t 4 sec is 4 10 m s 1 16 m s 2 18 m s 3 22 m s

Three balls are thrown from the top of a building with equal speeds at different angles When the balls strike the ground their speeds are V1 V2 and v3 respectively then 1 V V2 V3 2 V3 V2 V1 3 V V2 V3 4 V1 V2 V3

Direction Analyze the problem and answer the given questions Performance task Height in meters Horizontal distance in meters A bail on the football field was kicked by Bruno The parabolic path of the ball is traced by the graph above 1 How would you describe the graph 2 What is the initial height of the ball 3 What is the maximum height reach by the ball 4 Determine the horizontal distance that corresponds to the maximum height reached by the ball 5 Approximate the height of the ball it has travelled 3 meters horizontally 6 How far does the ball travel horizontally before it hits the ground

24 ner Two blocks of equal masses have been placed on two faces of a fixed wedge as shown in figure The lliw ditog bealm S to brege instappe niliw centre of one block is at a height h above the centre of other block The time after which the centre of two blocks will be at same level is blocks are released from position where centre of one bl 1 2h 2 2 2h m h m 60 30 3 2 3 h O 4 3h V g jong to olons uns

A boy in an elevator with open roof shoots a bullet in vertically upward direction from a height of 1 5 m above the floor of the elevator The initial speed of the bullet with respect to elevator is 15 m s The bullet strikes the floor after 2 seconds Then Assuming g 10 m s 1 Lift is moving with constant speed 2 Lift is moving with upward acceleration of 5 75 m 3 Lift is moving with downward acceleration of 5 75 m

20 Three stones are projected simultaneously with same speed v from top of a tower Stone 1 is projected horizontally other two makes an angle with horizontal as shown in figure Before stone 2 hite ground the distance between 1 and 3 was found to increase at constant rate 2 5 0 3 2 Then 1 Angle 0 is 37 2 Angle 0 is 60 3 Rate at which distance between 2 3 increase is 3 v 85 8 4 Rate at which distance between 2 3 increase is V Palm 6 S V gnols privom zi eline S

36 In the arrangement shown a and a are the acceleration of the two blocks 1 2 with respect to ground in upward direction and a be the magnitude of relative acceleration of each block with respect to lift Regarding the tension in the string the incorrect statement is m m m 1 4 T 2 m 1 T mg m a 2 T m g m a T m g a 2m m A Lift is accelerating up with acceleration a g a

1 A particle is moving along x axis Initially the distance of the particle from the origin is a and its velocity is zero The acceleration of the particle at any instant is given by f cosot sinot where t is time Then the maximum distance of the particle from the origin is 1 a 3 a 2 1 2 2 a 4 1 a 2 2 1

A block of mass 10 kg is tied with the help of string rests on an rough inclined plane u 0 5 as shown The frictional force on the block is g 10m s tan 0 9 42 1 50 N 10kg 30 0 9 2 25 3 N 3 100 N 4 Zero

i A particle is moving with uniform acceleration Its velocity after 48 is 17m s and 7s it is 26m s 1 Initial velocity 2 Velocity after 2s 3 Velocity after 6s 4 Velocity after 10s a 35m s b 11m s c 5m s d 23m s e 26m s a 21 12 7 3 of

The mass of a lift is 2000 kg When the tension in the supporting cable is 30000N then its acceleration is g 10m s 1 30 ms downwards 2 4 ms upwards 3 4 ms2 downwards 4 5 ms2upwards

A swimmer can swim in still water with speed v and the river is flowing with velocity v 2 To cross the river in shortest distance he should swim making angle with the upstream What is the ratio of the time taken to swim across the river in shortest time to that is swimming across over shortest distance 11 03

2 A particle is traveling on the path r t with acceleration vector 6t et 0 Initially at t 0 the particle is at the origin with initial speed 4 Its initial velocity is in the positive direction of 1 0 1 i e it is a positive scalar multiple of this vector a What is the initial velocity of the particle b Find r t

A man running on a horizontal road at 8 km h finds the rain falling vertically He increases his speed to 12 km h a finds that the drops make angle 30 with the vertical Find the velocity of the rain with respect to the road A 2 7 km h B 7 km h C 4 7 km h D 3 7 km h

Two particles A and B are projected simultaneously with speed of 20 2 m s and 20 m s from top of two building of height 60m and 80m as shown in figure Particle A is projected at an angle of 45 with the horizontal where as particle B is projected horizontally The distance between the building is 20 m Then find minimum distance between two particle A 4 5 m C 20 2 m B 12 5 m D 40 5 m 60m 2012m 45 d 20m 20m s 80m

A body is projected horizontally from the top of a tower with a velocity of 10 m s If it hits the ground at an angle 45 the vertical component of velocity when it hits ground is in m s O 10 10 2 LG Clear Response

Q5 of 90 Mark for review To reach your school at 10 30am let you start at 10 00am First you move 800m towards east then 600m towards north and finally 200m towards west Then net displacement is Clear Resp

body of mass 2 0 kg is at rest at height of 10 m above the ground Calcul LE after it has fallen through half the height tions 98 J 98 J 110 J 120 J 20 J 40 J 90 J 30 J

I I Column 1 System string 2k ing string Column 2 Extension in spring at equilibrium MAVEVA JATHE ii iii iv mg 4k mg k mg 2k Column 3 Maximum amplitude of block so that string attached to block does not slack 2mg k R S 4mg mg 8k mg k

2 The position x time t graph for a particle moving along a straight line is shown in figure The average speed of particle in time interval t 0 to f 8 sis x m 20 10 0 2 1 Zero 3 7 5 m s 468 A t s q 2 5 m s 4 9 7 m s IN

2 on ground both apply Newton s law and measure normal reaction on the body 0 m 79 7777 7777 1 The both measure the same value 2 The both measure different value 3 The both measure zero 4 Not sufficient data IS

Uniform and non uniform acceleration both Which of the following statement is 3 INCORRECT I For motion involving change in direction along the straight line displacement may decrease II Direction of acceleration is same as direction of velocity III Average speed is in general greater than or equal to the magnitude of the average velocity IV Equation of motion is valid only in one dimensional uniform accelerated motion 1 only I 5 II IV 2 only IV 4 I III IV

ubwards with speed vo The variation of speed with time is best represented by which of the following graph VA 445 3 2 Vo Vo fu

The position of a particle is given as 7 at bt 1 Find the a Equation of trajectory of the particle ns y bx a b Tangential normal acceleration and radius of curvature at t 1 sec 4b Re 462 3 2 la 4b 2ab ns a t an 2ab Va 4b 2

Part A options left to right or right to left Consider the parametric equations below x t 6 y t 3 a Describe the motion of the particle moving according to the parametric equations The motion of the particle is from Choose one b Find the equation of the curve along which the particle moves NOTE Enter the exact value

7 A projectile is projected with a speed u making an angle 20 with the horizontal What is the speed when its direction of motion makes an angle 0 with the horizontal u cos 20 2 1 2 u 2 cos 0 sec 0 3 u cos 0 4 u cos 0 sec 0 A particle reaches its heghest point when it has

SolveLancer Test A particle moves rd of total distance with an acceleration 10 m s starting from rest The remaining distance cover with constant velocity then find the ratio of time required to cover remaining distance and the total time Here total distance is 120 m SolveLancer Test a 1 5 b 1 4 c 2 5 4 23 0 a

A boy tries to cross the river and want to reach at the exactly opposite point on the other bank then what is the necessary relation between v and v I V velocity of boy v velocity of river b 1 v V 2 V V 3 V V 4 None of these

above the target 2 Pass below the target 3 Hit the target 4 Certainly miss the target Neglecting the air resistance the time of fligh of a projectile is determined by u 1 Uvertical component of velocity in vertica direction 2 Uhorizontal component of velocity in horizonta direction 3 u u u 4 u u u vertical inal horizontal 1 2

The velocity time graph of two particles moving along x axis is shown in figure At t 0 both were at origin During first 4 sec the instant when they are at maximum separation and the maximum separation are V m s 1 2 sec 4m 4 3 2 2 2 sec 32 7m t sec 3 16 7 sec 32 7 m 4 16 7 sec 4m

Curve representing path of the object 18 If v and a represent velocity and acceleration 18 respectively then v may remains applicable in 1 1 Dimensional motion 2 Projectile motion 3 Circular motion 4 None of the above ime relation

The component of a vector r along x axis will have maximum value if 1 F is along positive y axis 2 is along positive x axis 3 I makes an angle of 45 with the x axis 4 r is along negative y axis

of drop 3 At the top most point 4 Any where is between the poi projection and topmost point 4 A gun is aimed at a target in a line of its The target is released and allowed to fall gravity at the same instant the gun is fired bullet will 1 Pass above the target 2 Pass below the target 3 Hit the target 4

x m 60 50 40 30 20 10 1 2 3 4 5 A 6 t sec B Displacement time curve of two objects A is shown in the figure Find relative velocit B with respect to A 1 15 m s 2 10 m s