re-NEET// Warmup 01// NCERT Theory (XI Part 1)

Added: 2026-05-14

[00:00:26]Okay. Okay. Okay. Uh, okay. See Okay. Good evening. Good evening.

[00:01:19]Lina sounds first.

[00:01:50]Frankly speaking, I am still in a confused state.

[00:01:57]What to do? What strategy?

[00:02:28]Definitely no question. Okay.

[00:03:00]Definitely question.

[00:03:28]But level of preparation.

[00:03:46]Yeah, good question.

[00:04:17]Class 11 part one. Part one.

[00:04:45]after dead fullfledged definitely. Definitely one month.

[00:05:23]for level.

[00:05:48]Do not for questions.

[00:06:09]No mad Definitely.

[00:06:36]Okay.

[00:06:43]screen.

[00:07:00]Let's enjoy. Let's en enjoy this process.

[00:07:22]NCR screen.

[00:07:46]Class 11 part one 2026 first first measurement question One class that is physics class 11 part one theory Don't worry. Don't worry.

[00:09:02]significant figures change for example Number of significant figures.

[00:09:39]How many number of significant figures?

[00:10:00]So leading they are all nonsificant.

[00:10:25]But when we talk about they are not significant leading are not significant but for exampific So we cannot ignore this significant figures are significant 2.0 0 kilome number of significant figure is 2.0 3.0 zero. So the number of significant figure is two figure 2.0.

[00:11:50]This is wrong. 200 only one00 so whenever we convert from one unit to another unit very clear division plus.

[00:12:24]For example, least significant figure among a bific Figure multiplication 2.0.

[00:13:22]How many figures 2 1 figure significant figure one significant figure after decim After decimus after decimal 2 figure one significant figure problem.

[00:14:25]Okay. Now answer 3.

[00:14:34]So the answer is six. The answer is figure.

[00:14:54]So the answer should be answer should be good.

[00:15:03]Now division say 2.0 into say 1.00 into 300.

[00:15:17]Now significant figure now division number of significant figures least significant figure 2.0 significant figure 2 1.0 significant figure 3.0 significant figure four. So the answer should have overall now 2.

[00:15:58]So 6.0 zero significant figure rounding of round 2.3 significant figure two significant Uh after only decimal 2 So the answer only six and 6.0 different now overall figure overall. So overall 2.0 1 figure 3 3 significant figure overall two significant figures.

[00:17:50]So now round of round significant figure two significant figure 2.3 2.3 2.3 significant figures Round of 2.345 either 2.3.4 2.34 2.3 close 2.4 So 45 2.3 2.4 Now it is quite obvious it is closer to 2.3 2.3.4 is 2.4 Not 2.3 confusion 2.3 2.3 exactly 2.3 2.3 2.3 2 What should be the rule?

[00:19:50]What is the convention?

[00:20:02]either 2.4 2.2 either 2.4 2.2.2 2.2.3 2.3 2.4 2.43 1.12 Exactly.

[00:21:02]Even if 35 significant two significant figur 2.4 2.34.2 2.4 So the logic is very simple round.

[00:22:11]Then now tell me what should be the answer 2.35.3 definitely 2.4.4 Important 2.45 question 2.4 What should be your answer? What should be your answer?

[00:22:50]I 2.454 44 significant figure 2.4.

[00:23:04]2.5 2.4 2.4 2.4 2.4 2.5 2.45 2.4 important 2.5 I think you still do not get the answer 2.5.4 The difference between the difference between 2.5 and 2.454 is 0.046 What about 2.5 uh 2 4 2.454 2.4 difference 0.054 054. Now tell me rules for even older different opinion.

[00:25:03]Even 2.45 2.35 exactly 2.45 2.4 4 2.5 exact exact 2.35 2.3 2 exact 0.05 C 0.05.4 2.5 2.4D 2.2D 2.6 these are all possible values but 2.4 So 9,2.3 2.3 2.4 2.3 2.4 2.3 2.35 2.4 2.3 2.4 So 2.4 2.3 for 50 days.5 will be 2.5.

[00:27:34]So exam near 2026.

[00:28:01]2026 significant figure 2026 significant figure question.

[00:28:28]Figure question.

[00:28:53]questions.

[00:28:59]Okay.

[00:29:06]Good. Good. Question. Questions.

[00:29:16]measured to be 9 cm per side. Keeping this significant figure in view the density of the material of the cube can base express into heaven.

[00:29:53]question.

[00:30:07]Mass of the cube 5 kg 9.0 Density mass per unit volume very very simple formula 5.5ion 9.0 significant figure 5.5 580 significant figure. So answer number of significant figures should be the answer must have two significant figures overall option 7.654 option number B 7.7 C the 7.6 65.6.

[00:31:19]Now it is very very clear significant figure.

[00:31:27]So we are left with two possible options.

[00:31:36]5.59 final significant figure 964 678 67 cm cm.

[00:32:11]654 into 103.

[00:32:17]Now figure 7.6 7.7.6 But approximation definitely approximation.

[00:33:24]So when you do the round round the error you obtain should be minimum.

[00:33:31]So 2.6 closer to 7.7. So the answer should be 7.7.

[00:33:59]for this is my argument or this is my concept.

[00:34:33]different opinion but the concept is this whenever you do the approximation whenever you do the round off the error you obtain should be less that's Now the dimension of base quantities and combination of this combination describe the nature of physical quantity dimensional analysis dimensional consistency of the equation deducing relation among the physical quantities. Now Dimensionally 40 minutes.

[00:35:45]question.

[00:35:52]So warm up.

[00:36:21]A dimensionally consistent equation need not be actually an exact or correct equation. Dimension dimensionally wrong or inconsistent equation must be wrong.

[00:36:49]2 n. Now tell me incorrect equations.

[00:37:24]question.

[00:37:26]Now see dimensionally dimensionally number one number u equations Dimension.

[00:38:29]Dimensionally wrong.

[00:38:52]Don't worry.

[00:39:04]equationally correct. Dimensionally incorrect.

[00:39:21]What is the concept? What is the logic?

[00:39:28]Quite dangerous. Quite dangerous.

[00:39:40]Dimensionally incorrect numerically correct More second pressure.

[00:40:20]Pressure equals.

[00:40:43]So pressure equations.

[00:41:21]NCRT incorrect. Numerically correct.

[00:41:37]Anyway, anyway, next dimension analysis application.

[00:42:08]N12entity value force.

[00:42:36]particular.

[00:42:57]Now different represent value.

[00:43:16]Now inversely proportion You need value inversely.

[00:43:56]5 into 10^ - 3 which is 0.5 kractice.

[00:44:27]Very good. Very good.

[00:44:51]Very good. Very good.

[00:45:00]It will be a rectangular hyperola.

[00:45:06]Third quadrant.

[00:45:14]Very good.

[00:45:18]Next. Next. Next. Next.

[00:45:21]Next.

[00:45:26]Now motion in a straight line.

[00:45:30]Unifor motion. What is unifor motion?

[00:45:34]Uniform motion. Constantain velocity.

[00:45:38]Constant velocity. Moving in a straight line.

[00:45:42]Moving in a straight line at a constant speed without changing the direction.

[00:45:51]Straight line.

[00:46:01]My question is my purpose is not to teach a theory. Now my purpose is to heat up your brain.

[00:46:28]Now my question is uniform circular motion uniform motion is uniform circular motion uniform motion logic.

[00:46:59]Definition is very simple. Unifority moving in a straight line. Circular motion straight line. Circular motion.

[00:47:15]Very good. Acceleration should be zero.

[00:47:18]Acceleration should be zero.

[00:47:21]Acceleration should be zero. And is uniform circular motion. A uniform motion. No uniform circular motion is not a uniform motion.

[00:47:33]Uniform motion number one straight line direction changes.

[00:47:38]Direction changes that is velocity B vector is not constant.

[00:47:45]Acceleration is not zero. Acceleration is not zero.

[00:47:51]Good. Good. So uniform circular can apply equation in uniform circular motion.

[00:48:06]Can we apply chyntic equation in uniform circular motion? Answer equation uniform circular motion.

[00:48:29]Can we apply chyntic equation?

[00:48:34]V = U + A direct vector S= U + A² B² = U² + A do R vector U + A to NUS.

[00:48:57]Can we apply? Can we apply chyntic equation in uniform circular motion?

[00:49:07]No. Because acceleration is not same.

[00:49:18]Good. Good. As chyntic equation should be applied only when acceleration is constant. Very good. Very good.

[00:49:40]dynamic equation should be applied only when acceleration is constant because acceleration is not same.

[00:49:55]No, we cannot apply chynatic equation in uniform circular motion. Then why uniform circular motion applicable when acceleration is constant?

[00:50:10]Vector vector form of the acceleration is constant.

[00:50:16]When acceleration vector is constant, when acceleration vector is constant, acceleration vector Uniform circular motion is acceleration constant.

[00:50:38]Is acceleration constant in a uniform circular motion?

[00:50:43]Uniform circular motion. Acceleration always square by ran magnitude in a uniform circular motion.

[00:51:14]Acceleration is always acting towards the center.

[00:51:21]Acceleration is always Acceleration vector.

[00:51:47]Acceleration vector direction means I when the object is at this position center but direction is alongus I always acting towards the center but I direction even though The direction is always acting towards the center. Vector wise the vector is changing. So acceleration vector is not constant butt because many times many times acceleration but Good.

[00:52:58]Acceleration is always acting towards the center but vector wise it is not it is not constant. So is acceleration constant in uniform circular motion magnitude wise constant but vector- wise not constant.

[00:53:14]Tential acceleration uniform circular motion tential acceleration. In uniform circular motion there is no tential acceleration. Tential acceleration is zero.

[00:53:51]vertically.

[00:54:02]Why only Maxit Maxitive.

[00:54:54]What is the common sense?

[00:55:13]So now position and time graphel X velocity velocity dx by dt which is the slow acceleration dv by dtel Now slope zero that is velocity is zero.

[00:56:15]Velocity slope is negative.

[00:56:30]Bit right.

[00:56:36]So negative velocity velocity.

[00:56:45]So that means So negative is accelerating.

[00:57:16]Accelerating means It is accelerating. So accelerating positive acceleration.

[00:57:56]explanations.

[00:57:58]Now, next positive slope velocity is positive. Positive slope.

[00:58:18]Second slope velocity becomes negative.

[00:58:23]Positive velocity.

[00:58:37]Accelerate that is negative acceleration.

[00:58:55]con. So B is a conant. See the slope is conant.

[00:59:03]Slope is conant.

[00:59:06]Slope is constant velocity.

[00:59:13]So explanation.

[00:59:38]So far so good.

[00:59:49]foreign speech.

[01:00:11]Okay.

[01:00:15]forgiven.

[01:00:48]I don't even Foreign speech. Foreign speech. Foreign speech.

[01:01:35]question.

[01:01:47]So that A question 600.

[01:02:22]If level.

[01:02:27]Different question 600 Overidenties.

[01:03:39]confidence.

[01:03:57]individually.

[01:04:07]Foreest exam.

[01:04:34]But different opinions number Clear cut.

[01:05:11]for question.

[01:05:54]Okay.

[01:06:00]Fore restoration.

[01:06:20]Good sense.

[01:06:35]According offline.

[01:07:15]Good.

[01:07:30]PDF so that you can Don't worry.

[01:08:06]So, reaction time.

[01:08:30]Stopping distance or stopping time.

[01:08:35]Fore!

[01:08:40]Foreign! Foreign!

[01:08:50]I know your number.

[01:09:55]I don't know.

[01:09:57]Anyway, reaction time stopping time or stopping distance.

[01:10:15]Reaction time.

[01:10:44]time reaction time.

[01:11:04]reaction time. So stopping distance or stopping reaction distance.

[01:11:34]Stopping time. Stopping distance.

[01:11:43]Minimum stopping distance.

[01:11:46]Minimum stopping distance 40.

[01:11:57]stopping distance.

[01:12:23]Don't worry. Don't worry.

[01:12:32]purely question.

[01:12:37]So 40 question= U + A final velocity U² = - A S Similar Now next stopping distance. Stopping distance u proportionate stopping distance 2 / stopping distance of the first case will be equals to u2 by u1 square. So example that in other words stopping distance depends on what stopping time stopping b= a t equals tous. In other words, time stopping time.

[01:14:22]5 seconds.

[01:14:24]Stopping distance and stopping time.

[01:14:28]T2 by T1 will be equals to U2 by U1.

[01:14:41]or stopping reaction.

[01:14:46]Reaction time.

[01:14:50]And then reaction time.

[01:15:14]stopping actual sign of acceleration does not tell us whether the particle speed is increasing or decreasing.

[01:15:31]Acceleration depends on the choice of the positive.

[01:15:42]For example, acceleration. So in this case acceleration is negative but is decreasing acceleration.

[01:16:12]still increasing. So acceleration increasement question is positive speed will always increase. Speed will always decrease.

[01:16:50]choice depend sorry velocity that is acceleration velocity number acceleration must be zero acceleration must be greater than zero or whatever Velocity that is moment.

[01:17:41]velocity.

[01:18:02]Velocity or velocity 0 Speed.

[01:18:11]Acceleration.

[01:18:28]But for example, velocity is not zero but velocity zero example is above at the extreme position of a pendulum. Very good.

[01:19:45]Very good. Very good. Very good.

[01:19:49]Next motion in a plane.

[01:20:00]See equations y = tan theta xus gx² u x² or u co whatever here don't forget this now y = a - bx² obviously motion is a parabolic.

[01:20:41]Now range of the projectile xicid very very simple example y = 4xus 2x² 16 example 16 x² x² Now range is 4x 16 1x 4 m. So this is your very simple. So equation for uniformation do not apply in the case of uniform circular motion. Since in this case magnitude of acceleration is constant but each direction is changing. In short acceleration vector is not constant.

[01:21:47]Resulting acceleration of an object in a circular motion is acting towards the center only if circular motion uniform circular motion acceleration is always acting towards towards center. Now uniform circular motion the acceleration is always acting towards the center vector is not acceleration vector.

[01:22:18]Now the next question answer in a circular motion in a circular motion acceleration is always acting towards towards center.

[01:22:35]True or false? Question.

[01:22:40]In a circular motion acceleration is always acting towards the center.

[01:22:53]In a circular motion, acceleration is always acting towards the center. True or false?

[01:23:08]Post pose. Very good. Very good. Reason uniform circular motion.

[01:23:17]Noniform circular motion.

[01:23:27]Circular mot.

[01:23:39]Whenever they say acceleration only when the motion is uniform circular motion good if nonform this is false Next. Next question.

[01:24:07]In a more circular motion, the acceleration could be acting tangentially.

[01:24:21]Whenever I say acceleration, we mean the net acceleration. We mean the net acceleration.

[01:24:28]True.

[01:24:30]In a circular motion, the acceleration could be acting tangentially.

[01:24:41]True or false? True.

[01:24:45]Question number two. Question number two. True false.

[01:24:50]In a circular motion, acceleration could be along the tension.

[01:24:56]And the explanation why true why reason to circular motion.

[01:25:36]Alo towards the center.

[01:26:02]So tent Clear.

[01:26:26]Circular motion. Unifority always square R omega square AL R Alpha R alpha R alpha as to keep the motion to have a circular part.

[01:27:16]Circular motion or circular path change speed. Change speed. Change in speed.

[01:27:46]Change velocity. Change speed. Change velocity.

[01:27:58]Velocity.

[01:28:04]Good. Good. Change velocity. SP I'm not a teaching theory now. I'm just reminding I'm just warming up.

[01:28:36]So change velocity change speed change velocity change velocity d omega dt acceleration dv by dtel dv by dtelation Omega DT as D omega by D A tangent law a centrip.

[01:29:37]Hello.

[01:29:43]Very good. Very good.

[01:29:57]Magnitude of velocity velocity magnitude change. There is speed.

[01:30:32]Okay. Okay.

[01:30:37]It should be what I want to mean.

[01:30:48]So d omega by dt.

[01:31:02]Very good. Very good.

[01:31:06]Omega.

[01:31:16]Good. Good. Good.

[01:31:19]Now the last whatever.

[01:31:38]Read each statement below carefully and state with a reasonam and example if it is true or false.

[01:31:46]A scalar quantity is one that scalar quantity is in a processantity with example Why quantity example?

[01:32:56]Very good.

[01:33:20]Good.

[01:33:22]Can never take negative values. True.

[01:33:26]through does not vary from one point to another in space. Example, potential energy potential energy has the same value for observers with different orientation of the axis.

[01:34:27]has the same value for observers with different orientation of axis. Yes.

[01:34:37]So this is true.

[01:34:50]has the same value for observers with different orientation of frame of reference.

[01:35:00]Frame of reference.

[01:35:19]discuss for Google. Google 25 nothing unknown number.

[01:36:42]for with this.

[01:37:05]Bye. Good night. See you tomorrow.