## Kumar Ketan is teaching live on Unacademy Plus

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18.2k views unacademy Kumar Ketan Educator since January 2018 #6 years teaching experience #IIT JEE Physics #YouTuber (140k+ subs) #Unacademy educator(16k+ lifetimeviews) #Under graduate topper Follow me on the Unacademy Learning App 1k Followers Following Courses Get updates about new courses Watch all my lessons .Download slides and watch offline All courses HINDI Relative Motion (Hindi) Kinematics: Relative Motion Rain Drop and Boat River Proble.. 5.0 (5 ratings) Kumar Ketan Kumar Ketan

CRAs4 Physics course for IIT JEE Kinematics & Dynamics 1D Non-Accelerated Motion 1D Accelerated Motion Force Frictional Force Newton's Law of Motion Relative Motion

Average velocity for one dimensional motion (a) Suppose a particle in one dimensional motion covers distance Xi, in time t1 with velocity Vi and then it covers distance x2, in time t2 with velocity v2. The average velocity of the particle is given by anti+t2 vi 2

(b) If a particle, in one dimensional motion covers (x/n)th distance with velocity V , next (x/n)th distance with velocity v2, next (x/n)th with velocity v3, and so on last (x/n)th distance with velocity Vn, then the average velocity is the Harmonic mean of v , V2, V3, 0)

A boy walks to his school at a distance of 6 km with a speed of 2.5 km/h and walks back with a constant speed of 5 km/h. His average speed for round trip expressed in km/h is (A)24/13 (B) 10/3 (C) 4.8

we know that 01 'U2 2n GD an, according to questior 1 + 1 U1 'U2 10 1 2 0t5+5255 as 3 5 2 1 1O 3

A car covers 1/3 distance with speed 20 km/h and 2/3 with 60 km/h. Average speed is (A) 40 km/h (C) 36 km/h (B) 50V2 km/h (D) 80 km/h

In 1st case: Distance covered by car, x1-/3 km Speed, V20km/h Hence, time taken, t1 = x/v1-1/60 h In 2nd case: Distance covered by car, X2- Speed, v2- 60 km/h Hence, time taken, tz 1/90 h Therefore, av. speed Total distance covered / Total time taken = x1+x2/t1-t2

The car travelling on a straight track moves with uniform velocity of v for some time and with uniform velocity v2 for the next equal time the average velocity of the car is: (a) Viv2/2 b) VV2/4 (c) Vr+V2/2 (d) Vr-V2/2

Average velocity is given by total displacement total time x1 + x2 = a0 because x=vt therefore v., - htta now, substituting ti - tt, we get la a)

. Suppose a particle starts from rest and accelerates at the rate for time t1 over a distance x1 and then retards to rest at the rate for time t2 over distance X2. Then : The maximum velocity of the particle 2 (x1 + x2) 2 Umax

. The distance covered by a particle in nth second is given by: Xn u a(2n-1)/2 Here, the dimensions of Sn are the same as that of velocity

Points to Remember For one dimensional motion the angle betweer a and v, is either 0 or 180%. And it does not change with time. . For two dimensional motion, the angle between a and v is other than 0 or 180 . Also it may change with time.

Average speed 2 magnitude of average velocity. . Bodies travel the same distance in last one second of their upward journey irrespective of their velocities AT

A train accelerates from rest at a constant rate for distance x1 and time ti. After that it retards to rest at constant rate for distance X2 and time t2. Which of the following relations is correct? AT

As we know that According to question,