IIT (NTSE/Olympiad)
Newton's Laws Of Motion & Friction
8. Motion of bodies in contact
8. Motion of connected Bodies
Case (A) :
For two Bodies :
F is the pull on body A of mass m1. The pull of A on B is exercised as tension through the string connecting A and B. The value of tension throughout the string is T only.
But this manifests as a pull T on B and a "reaction pull" T on A the free body diagram in this case are shown as follows.

Note : The spring is massless
Free body diagrams :
⇒
Case (B) :
For Three bodies :
Free body diagrams :
⇒
Case (A) :
For two Bodies :
F is the pull on body A of mass m1. The pull of A on B is exercised as tension through the string connecting A and B. The value of tension throughout the string is T only.
But this manifests as a pull T on B and a "reaction pull" T on A the free body diagram in this case are shown as follows.

Note : The spring is massless
Free body diagrams :
For body A | For body B |
---|---|
![]() | ![]() |
R1= m1g F – T = m1a | R2= m2g T = m2a |
⇒

Case (B) :
For Three bodies :

Free body diagrams :
For A | For B | For C |
---|---|---|
![]() R1= m1g T1= m1a | ![]() R2= m2g T2– T1= m2a ⇒ T2= m2a + T1 T2= (m2 + m1)a | ![]() R3= m3g F – T2= m3a ⇒ F = m3a + T2 = m3a + (m1 + m2)a F = (m1 + m2 + m3)a |
⇒

IIT (Class X)
- Unit, Dimension & Error
- Vectors
- Motion in One Dimension
- PROJECTILE MOTION
- NEWTON'S LAWS OF MOTION & FRICTION
- 1. First Law Of Motion
- 2. Second Law Of Motion
- 3. Third Law Of Motion
- 4. Reference Frames
- 5. Motion in a lift
- 6. Motion of a Block on a Horizontal Smooth Surface
- 7. Motion of bodies in contact
- 8. Motion of connected Bodies
- 9. Motion of a body on a smooth inclined plane
- 10. Motion of two bodies connected by a string
- 11. Friction and frictional force
- 12. Graphical representation of friction
- 13. Types of frictional force and their definition
- 14. Angle of Friction
- 15. Minimum force Required to move a block
- Points to Remember - Newton's Laws Of Motion & Friction
- WORK, POWER, ENERGY & CONSERVATION LAWS
- CIRCULAR MOTION & ROTATIONAL DYNAMICS
- GRAVITATION