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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
FORCE Force as an external effort in the form of push or pull, which (i) produces or tries to produce motion in a body at rest, or (ii) stops or tries to stop a moving body, or (iii) changes or tries to change the direction of motion of the body.
1.Inertia The property of a body to continue in its state of rest or that of uniform motion in a straight line in the absence of external force is called inertia. Newton's first law of motion is the law of inertia. 2. Momentum The product of mass (M) of a body and its velocity (v) is called momentum (p"). Thus p Mv. Its unit is kg m/s.
3. Newton's second law of motion- This law states that the time rate of change of momentum is equal to the applied force (F). That is IS: dp /dt Where a" - dv'/dt is the acceleration of the body
However, if the force acts and velocity remains constant, then we find: Such is the case with system having variable mass
4. Impulse- The product of force (F) and the time interval (dt) for which the force acts is called impulse (i) That is The unit of impulse is Ns. It is equivalent to kg m/s.
5. The impulse is also equal to the area between the time axis and F-t graph. Impulse area
6. Newton's third law of motion To every action (A"), there is equal and opposite reaction (R"). That is The action as well as reaction of forces acting on different bodies. herefore they do not cancel each other. They are mutual forces. One is the cause of the other and exist simultaneously.
Mass varies with velocity, hence F dp/ dt
Because F Ma is applicable when mass does not vary. In case of the rocket, the mass continuously varies.