Problem applying Newtons third law

AI Thread Summary
The discussion centers on a physics problem involving two skaters pulling on a rope and the application of Newton's third law. One skater exerts a force of 35N on the rope, leading to confusion about how this force affects each skater's acceleration. The consensus is that each skater experiences a 35N force, not a split force, resulting in both skaters accelerating toward each other. The correct time for them to meet is confirmed to be 5.5 seconds, aligning with the calculations based on the forces involved. The clarification emphasizes the importance of understanding force interactions in accordance with Newton's laws.
Neil Melnick
Messages
1
Reaction score
0

Homework Statement


Two people each with a mass of 70kg are wearing in line skates and holding opposite ends of a 15m rope. One person pulls forward on the rope by moving hand over hand and gradually reeling in more of the rope. In doing so, he exerts a force of 35N (backwards) on the rope. This causes him to accelerate toward the other person. Assuming that the friction on the skaters is negligible, how long will it take for them to meet? Explain.

Homework Equations


F=MA and D= T x init. Veloc.+ 0.5 AT²

The Attempt at a Solution


Book says 7.7, I say 5.5. Book splits the 35N between the two masses, I say equal and opposite means 35N acts on each. Consulted with several engineers, no consensus. Help!
 
Physics news on Phys.org
Welcome to PF!

Your answer of 5.5 seconds is correct. The tension in the rope will be 35 N. Each person is acted on by a 35 N tension force from the rope.
 
  • Like
Likes Neil Melnick and CWatters
There will be 35 N forces acting on both persons. There is no "splitting".
 
  • Like
Likes Neil Melnick and CWatters
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »

Similar threads

Newton's Third Law for book on a table
Replies
8
Views
3K
Where does Newton's third law fail?
Replies
9
Views
2K
Newton's Third Law Problem: Two masses, a rope and a pulley
Replies
21
Views
10K
Understanding the Third Law of Newton — How can the forces be equal?
Replies
7
Views
2K
Why doesn't Newtons third law also apply to the frame?
Replies
2
Views
2K
Is it friction or tension acting on the person hanging on a rope?
Replies
4
Views
990
How Does Newton's Third Law Apply When a Bat Hits a Ball?
Replies
11
Views
3K
Understanding Newton's Third Law in Action: A Truck Pushing an SUV
Replies
4
Views
2K
Newton's Third Law and Car Crashes
Replies
7
Views
3K
Newton's third law: Rower makes boat move forward
Replies
2
Views
6K

Hot Threads

Recent Insights

Back
Top