Problem understanding Newtons third law ...

Click For Summary
SUMMARY

The discussion centers on the application of Newton's Third Law in a problem involving three blocks on a frictionless surface. A 42N force acts on a 3kg block, while a 14N force is exerted by the 1kg block on the 2kg block. The confusion arises regarding the force exerted by the 2kg block on the 1kg block, with participants clarifying that the tension in the connecting string must also be considered. The conclusion emphasizes that all forces, including tension, must be accounted for to understand the motion of the blocks accurately.

PREREQUISITES
  • Understanding of Newton's Laws of Motion
  • Basic knowledge of force and mass (F=ma)
  • Concept of tension in connected systems
  • Frictionless surface dynamics
NEXT STEPS
  • Study Newton's Third Law of Motion in detail
  • Learn about tension forces in connected objects
  • Explore problems involving frictionless surfaces and multiple bodies
  • Review dynamics of systems with multiple forces acting simultaneously
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of force and motion in connected systems.

Warlic
Messages
32
Reaction score
0

Homework Statement



upload_2015-11-5_19-55-25.png
[/B]
Three blocks move on a frictionless surface and a 42N force acts on the 3kg block.
The force exerted by the 1 kg block on the 2 kg block is 14N.

What is then the force exerted by the 2 kg block on the 1kg block? If it is 14N, then shouldn't the 2kg block stay in place and not move? Shouldn't then the 1kg block also stay in place?

2. Homework Equations

F=ma?

The Attempt at a Solution

 
Physics news on Phys.org
upload_2015-11-5_20-2-15.png

This would be the correct figure; 3kg block pulled by a force of 42N, and the 1 kg and 3kg block are connected by a string.
 
Warlic said:
If it is 14N, then shouldn't the 2kg block stay in place and not move? Shouldn't then the 1kg block also stay in place?

Don't forget the force applied due to the string connecting the blocks; the 14N-force isn't the only one affecting the block 1/2 - system.
 

Similar threads

Replies
13
Views
3K
  • · Replies 8 ·
Replies
8
Views
4K
Replies
16
Views
3K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 25 ·
Replies
25
Views
2K
Replies
37
Views
4K
Replies
1
Views
3K
Replies
2
Views
1K
  • · Replies 21 ·
Replies
21
Views
11K
  • · Replies 1 ·
Replies
1
Views
3K