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High School/JEE/NEET/IPhO Physics | 17-19 Yrs

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  1.  
    2. Sir in this solved example, when the plane is flowing from B to C, it is agreed that V of PG is the resultant. But shouldn't the magnitude be root of Vp^2 Vw^2. I didn't understand this. Can you please explain it to me sir.
    1 years ago by Vijayasimha.S.Kulkarni

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  2.  
    3. Sorry
    3 years ago by Amit kumar

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  3.  
    4. Post your query related to above video lecture
    3 years ago by Amit kumar

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  4.  
    5. there for resultant why sir used v(vp²-Vw²) except of + sign
    4 years ago by Tech X

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  5.  
    6. sir why did u take negative sign for velocity of river
    4 years ago by

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  6.  
    7. sir tan(theta)is Vr/Vm ...........it was written Vm/Vr........?...plz correct it sir
    4 years ago by YASHWANTH REDDY CHENNURU

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  7.  
    8. sir why couldn't we directly write vs sin?= uf to balance the horizontal components(to get zero horizontal velocity component and so the boat wouldn't drift)
    4 years ago by Arya Kavita Dwadasi

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  8.  
    9. Can we don't solve the question set? If yes then how because it is going to open the video in YouTube.
    5 years ago by

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  9.  
    10. Why Quset 1 problem are not showing?
    5 years ago by Dharamjeet Singh

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  10.  
    11. sir in the question the speed is given in kph.....but without converting it into SI m/s..in the answer you wrote m/s..how is it possible? Please explain sir.
    5 years ago by Goutham K

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  11.  
    12. A block is thrown with velocity of 2 metre per second relative to ground on a well which is moving with a velocity of 4 metre per second in opposite direction of the initial velocity of block if the block stop slipping on the belt after 4 seconds of throwing then choose the correct statements
    5 years ago by Shivam Yadav

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  12.  
    13. When we find the magnitude would there not be a plus sign along with Vw rather than a minus sign at 3:12?
    6 years ago by Madhav Sharma

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  13.  
    14. can anyone explain me that how a cotton bag will not wet if rainfall is going on as given in module 11
    6 years ago by Subham Tiwari

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  14.  
    15. sir shouldn't the direction be 53 degree west of south in 3:00-3:02 ??
    6 years ago by Divit Goyal

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  15.  
    16. My best teacher For ashish arora sir Very very thank sir ????????????
    6 years ago by Aditya Pathak

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  16.  
    17. sorry by mistake i have wriiten zero my question is why displacement is negative?
    6 years ago by Divit Goyal

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  17.  
    18. sir with reference to scooter why will displacement be zero??
    6 years ago by Divit Goyal

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  18.  
    19. isnt the distance covered by a in that time 2d?
    6 years ago by Aatreya Kapoor

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  19.  
    20. A man running on a horizontal road at 8kph findsrain falling vertically.He increases his speed to 12kph and finds that the drops make angle 30 with the vertical. Find the speed and direction of the rain wrt the road.
    7 years ago by sg24062000@gmail.com

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  20.  
    21. sir here why we have taken negative vector and solved this
    7 years ago by Kalyan Purimetla

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  21.  
    22. In upstream case why the total drift is BC but not distance between the point where it would have reached and the point where it has reached?
    7 years ago by Aditya Raman
    Ans 1 ->
    cuz that is the definition of drift.
    6 years ago by Aatreya Kapoor

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  22.  
    23. Sir,In the example of Earth and Asteroid collision you have written that Vce=Vc-Ve right but my doubt is we must write this equation only in one dimensional motion or not
    7 years ago by Neelesh

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  23.  
    24. How we'll come to know if the two bodies are colliding??
    7 years ago by Nevil Tanna
    Ans 1 ->
    If two bodies are approaching perpendicular to each other then the condition for collision is...they must posses equal velcities if they are initially started from equal distances....and next one is ...f they didnot started from equal distances but mentioned that condition for ccollision means we must assume that they will collide at some point and we must calculate the distance from their collision to thei starting point and we must calculate velocities for those vehicles even accelerations also so that we can say that they will collide if they travel with these velocities and accelerations even though they did not started from equal distances.....this is the way to look at the problem if you understand my concept thank you ...and text to my gmail 'neeleshjanga14@gmail.com'..and i am a student of ASHISH ARORA sir through this site..
    7 years ago by Neelesh

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  24.  
    25. i think in the second last step it should be => 3d=5 * d/Vb - 10
    7 years ago by SAI
    Ans 1 ->
    no it should be d because they are originally at a separation 2d and then in that time t A covered a distance d
    6 years ago by aaditya chaturmohta

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  25.  
    26. SIR! CAN YOU PLEASE EXPLAIN THE CONCEPT OF RELATIVE MOTION WHEN TWO PARTICLES ARE PROJECTED SIMULTANIOUSLY FROM SAME OR DIFFERENT INCLINED PLANES
    7 years ago by manvendra

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  26.  
    27. SIR! CAN YOU PLEASE EXPLAIN THE CONCEPT OF RELATIVE MOTION WHEN TWO PARTICLES ARE PROJECTED SIMULTANIOUSLY FROM SAME OR DIFFERENT INCLINED PLANES
    7 years ago by manvendra

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  27.  
    28. What if we did this problem with reference to the scooter? V_BwrtS = 5m/s and will the displacement of 80 metres be negative or positive? or is it so that doing the problem wrt the scooter is the wrong method altogether?
    8 years ago by Rohit Sanjay
    Ans 1 ->
    as seen from scooter the bus moves backward so distance is negative velocity will be positive .
    7 years ago by SAI

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  28.  
    29. Sir, while differentiating with respect to theta what happened to the 'd'? Lenght of river??
    8 years ago by Harish D
    Ans 1 ->
    it got removed by dividing it on the rhs after differenciation as constant is removed out while differentiating
    7 years ago by Shantanu Kapoor
    Ans 2 ->
    sir can't we simply find theta in this case as we did in the previous example ??
    7 years ago by
    Ans 3 ->
    as we r equating dx/d(theta) =0 ... as we take d common and take it to other side.. it cancels out
    6 years ago by Àshütøsh Shårmå

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  29.  
    30. Could we just equate the Velocity of cyclist as seen by old man and velocity of boy as seen by old man? and get the answer ? as he meets them together. their velocities wrt to him should be equal right?
    8 years ago by Harish D

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  30.  
    31. sir in earlier modules you said that when velocities are in same direction then they have to be subtracted to find relative velocity but in this question along AB vw and vp are in same direction but you have added them
    8 years ago by sagar

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  31.  
    32. why the velocity of the truck is taken in backwards direction
    8 years ago by dhanush tummala

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  32.  
    33. if the thief is considered to be at rest why his velocity is taken as 9 m/s in the formula if he is at rest his velocity should be zero
    8 years ago by Keshav Aggarwal
    Ans 1 ->
    his velocity is not taken as 9m/s instead as we know that the thief was running at the speed 9m/s and the policeman was moving at 10m/s so if we consider thief at rest then what we did is that subtract 9m/s from its original velocity which results in 0m/s and so we have to do the same for the velocity of policeman i.e. subtract 9m/s which gives us 10-9=1m/s
    6 years ago by aaditya chaturmohta

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  33.  
    34. ANOMALOUS SITUATION!!!!!!!!!! Two cars distanced 4 m apart, initially moving at speeds 7 and 8 m/s towards each other immediately apply a retardation of equal magnitudes. Find the minimum retardation. ANOMALY: If I consider a relative frame, I get r = retardation = 225/16 (m/s)/s If I consider separate distances travvelled, i.e., x and y, and using the sum of distances = 4 m, I get: r = 113/16 (m/s)/s Why is this happening?!
    8 years ago by PSai Krishna Kvmb
    Ans 1 ->
    If retardation is considered negative acceleration in car consistently then second method is wrong as to avoid collision it is not necessary that both cars come to rest at the same time... they may be moving at same speed when their position is getting same... after that instant one can accelerate and other can retard and due to this separation starts increasing... But as cars generally do not accelerate in reverse so we can solve with second method here...
    8 years ago by Physics Galaxy

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  34.  
    35. VERY VERY HELPFUL VIDEOS!
    8 years ago by PSai Krishna Kvmb
    Ans 1 ->
    We are happy to know that these videos are helping you... if you like then recommend our website to your friends and in your circle...
    8 years ago by Physics Galaxy

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  35.  
    36. Sir. In laws of motion chapter of hcv exercise ques.40 will initial velocity be vsin(?°) or zero. I took vsin(?°) and answer i got was wrong. Pls help
    8 years ago by Anuj khare
    Ans 1 ->
    Here in reference frame of elevator you need to take initial velocity zero only... and as elevator is moving at uniform velocity... you can consider acceleration of block as g sinT only... you will get the correct ans...
    8 years ago by Physics Galaxy

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  36.  
    37. How did he caluculate Vbc
    8 years ago by aiswarya rallapalli

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  37.  
    38. D/Vb-10 is d common time .... but how does he know dat it travels d units in dis time period
    8 years ago by aiswarya rallapalli
    Ans 1 ->
    Well thats wat d question is
    8 years ago by aiswarya rallapalli

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  38.  
    39. why +5 is considered apart from -5 in the last expression.. as relative velocity of A wrt C is -5..please help!!!
    9 years ago by shreya sood
    Ans 1 ->
    its seems like a silly mistake please consider that to be -5
    6 years ago by Rajesh kumar yadav

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  39.  
    40. sir but answer comes out to be 25m/s as its d/3 = 5 * (d/vb-10)
    9 years ago by Abhisek Sahoo
    Ans 1 ->
    the distance walked by A is 3d-2d=d therefore the equation is correct
    9 years ago by Mohammad Shehzaad

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  40.  
    41. Why net velocity is root of Vs square-Vf square not root of Vs square+Vf square?please explain
    9 years ago by Arnab Pradhan
    Ans 1 ->
    apply pythagoras theorem in vector triangle and you get your answer
    8 years ago by Paresh Chaudhari
    Ans 2 ->
    sir plz explain I cant understand.
    7 years ago by Shashank Sudhir Dikkar

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  41.  
    42. swimmer crosses a river with minimum possible time 10 seconds. And when he reaches the other end he starts swimming in the direction towards the point from where he started swimming Keeping the direction fixed the swimmer crosses the river in 15 seconds. The ratio of the speed of swimmer with respect to water and speed of river flow is
    9 years ago by Harsh Sharma

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  42.  
    43. Sir please solve the ques no 6 ( QuSet 1) Two trains.......
    9 years ago by Priyanshu Varshney

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  43.  
    44. is our video is enough for jee
    9 years ago by Satyam Prakash Singh
    Ans 1 ->
    U need to practice more questions this is just developing a concept !
    9 years ago by Rahul Chauhan
    Ans 2 ->
    No beta first study ncert then theory of h.c.V then watch videos to have complete knowledge and clear understanding then solve h.c.v questions and last 10 to 20 years questions that will be enough best of luck
    9 years ago by Gurpreet Singh

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  44.  
    45. sir why you taken the time same as speed are different
    9 years ago by pranshu nema
    Ans 1 ->
    in ques it's given that the old man want to meet both cycle and boy together i.e . at same time.
    9 years ago by vivek solanki

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  45.  
    46. Sir I did not understand why the velocities got added when they are travelling with opposite direction. Could you please explain it
    9 years ago by Anagh Dave
    Ans 1 ->
    relative velocity=(velocity 1 - velocity 2)...since velocity 2 is in opposite direction it carries a negative (-) sign with it.Thus vel.1-(-vel2)=vel.1 +vel.2...i hope that might be the answer for your querry....
    9 years ago by sumit choudhary
    Ans 2 ->
    Try to learn physics by observing. When we are travelling in train and another train passes opposite to us it seems at a huge speed basically what happens let our speed be or rather velocity be V and that of other train be U and we know relative velocity of A with respect to B is VELOCITY OF A MINUS(-) VELOCITY OF B which in our case of train is V-U but concentrate on velocity direction both are in opposite direction so actually it V-(-U) which gives V+U hence ur answer. Now think when we see a train moving parallel to our train in same direction it velocity seems to be much less and in case both have same velocity the it seems us to be at rest because V-U BECOME zero. Try to observe and learn
    9 years ago by Gurpreet Singh

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  46.  
    47. how can we solve least distance of approach problems if the angle between the paths of two particle is not 90 degrees?
    10 years ago by Piyush bhardwaj

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  47.  
    48. Two cars A and B moving on two intersecting roads at an angle ???have uniform velocity u and v respectively. Their initial distances from the point of intersection are a and b respectively. Calculate the minimum distance of approach between the two cars. using vector analysis....
    10 years ago by Ajay
    Ans 1 ->
    Here you can find the distance between the two cards as a function of time and then differentiate it with respect to time to get the time at which this will be minimum and then substitute this time in the distance relation to get the minimum time.
    10 years ago by Physics Galaxy

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  48.  
    49. (vi) Two junglemen are standing at the two opposite banks of a river facing each other. One of them starts beating a drum and sound reaches to the other one after time t1 hestarts. Then second one starts beating the drum and now first one hear the sound after time t2. Calculate the velocity of sound relative to air an the velocity of wind, if it is blowing from first bank to the other bank at right angle to the river flow. (vii) A rectangular reservoir has a 1 km difference between its sides Two fishermen simultaneously leave one vertex of the rectangle for a point located at the opposite vertex One fisherman crosses the reservoir in a boat, the other walks along the bank Find the Size of the reservoir, of each of them has a speed of 4 km/hr and one of them arrives half an hour earlier than the other.
    10 years ago by Mukul Mahaliyan

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  49.  
    50. sir,can you please explain the concept of relative angular velocity?
    11 years ago by ramesh ammanamanchi
    Ans 1 ->
    ya sure
    10 years ago by satyajit satyaprakash
    Ans 2 ->
    relative angular velocity of a point with respect to other can be calculated by the ratio of relative velocity of one in the direction normal to line joining the two particles and the separation between the two particles.
    10 years ago by Physics Galaxy

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  50.  
    51. sir,can you please explain the concept of relative angular velocity?
    11 years ago by ramesh ammanamanchi
    Ans 1 ->
    relative angular velocity of a point with respect to other can be calculated by the ratio of relative velocity of one in the direction normal to line joining the two particles and the separation between the two particles.
    10 years ago by Physics Galaxy

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  51.  
    52. To find DC we are using the time taken for covering d, or say time taken for covering xd. How?
    11 years ago by Pranjal
    Ans 1 ->
    This is because the time taken to cross the river(width d) is the same time for which the swimmer is drifted by DC. Or by the time he crosses the river the velocity of river causes him to drift by dc.
    9 years ago by Ritwik Jha

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