## Kumar Ketan is teaching live on Unacademy Plus

ne

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

. 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

. If a particle accelerate from rest at the rate a1 for time ti and over a distance x1 and then it retards to rest at the rate a2 for time t2 and over a distance X2, then: a2 t 1 (ii) Maximum velocity attained is given by = all,!

. 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

A body starts from rest, what is the ratio of the distance travelled by the body during the 4th and 3rd seconds? (B) 5/7 (C) 7/3 (D) 3/7

Kn = u + a(2n-1)/2 = a(2n-1)/2, because u = 0 Hence, X4/X3 = (2x 4-1)/(2 3-1) = (8-1)/(6-1)-7/5

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.

.If the angle between a and v is 0 or 180 the path of the particle is a straight line. .If the angle between a and v is other than 0 or 180%, the path of the particle is a curve. . If the angle between a and v is 90%, the path of the particle is a circle.

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

As we know that According to question,

When the particle starts from rest, its initial velocity is zero i.e. u 0 The acceleration a is +VE when the particle speeds up and a is -VE when the particle speed down (retards)

A horizontal wind is blowing with a velocity v towards north-east. A man starts running towards north with acceleration a. The time after which man will feel the wind blowing towards east is (a) v/a (c) v/V2a (b) V2v/a (d) 2v/a

(j

um