Newtonian Mechanics/Forces Question

In summary: Thanks for catching that!In summary, the tension in the upper cord (T1) and the lower cord (T2) is increased when the apparatus is accelerated upwards.
  • #1
MyNameIsNicholas
4
0
Member advised to use the homework template for posts in the homework sections of PF.
4_41.gif


These buckets are being suspended. The cords have no mass and each bucket is 3.5 kg.

a.) Find the tension in the upper cord (T1) and the lower cord (T2)
b.) If the apparatus is pulled upwards from the top of the upper cord, what are the new tensions of each cord?

I understand the first part. The force diagrams consist of:
(Upper Bucket): T1 upwards, T2 downwards, and Fg downwards
(Lower Bucket): T2 upwards and Fg downwards

However, when the apparatus accelerates upwards, the tensions in both cords increases. This makes sense physically but in the force diagram isn't force applied (causing acceleration) going upwards? And if that were the case, then force applied would counter-intuitively decrease the tension within the cords. Can someone graciously clear this up for me?
 
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  • #2
Newton's second law applies to each bucket independently.
 
  • #3
MyNameIsNicholas said:
4_41.gif


These buckets are being suspended. The cords have no mass and each bucket is 3.5 kg.

a.) Find the tension in the upper cord (T1) and the lower cord (T2)
b.) If the apparatus is pulled upwards from the top of the upper cord, what are the new tensions of each cord?

I understand the first part. The force diagrams consist of:
(Upper Bucket): T1 upwards, T2 downwards, and Fg downwards
(Lower Bucket): T2 upwards and Fg downwards

However, when the apparatus accelerates upwards, the tensions in both cords increases. This makes sense physically but in the force diagram isn't force applied (causing acceleration) going upwards? And if that were the case, then force applied would counter-intuitively decrease the tension within the cords. Can someone graciously clear this up for me?
I'm not sure why you would believe that's the case, but look at ##\sum F = ma##. Solve for the tension, and you'll see why hopefully. You may be confusing systems in equilibrium and accelerating systems while doing the FD.

Edit, trying to think of a good way to explain what I think is catching you up, but anyway, what's actually accelerating the system upward? The reactionary tension of course! The force that's pulling the system upward itself isn't applied to the buckets, its mediated by the tension in the rope.

Not sure if that helps or not.
 
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  • #4
I think I understand! The FA isn't actually an applied force. Well it is, but in terms of this problem it isn't. It's actually just addition upward tensional force on the upper cord FT1! This would, obviously, increase FT1 and in turn increase FT2. Thanks for the help and sorry for not using the proper format of my question. Merci.
 

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  • #5
MyNameIsNicholas said:
I think I understand! The FA isn't actually an applied force. Well it is, but in terms of this problem it isn't. It's actually just addition upward tensional force on the upper cord FT1! This would, obviously, increase FT1 and in turn increase FT2. Thanks for the help and sorry for not using the proper format of my question. Merci.

Edit: Ignore those files. I was going to ask a follow-up question but upon creating those images and thinking about the question, it clicked!
 

What is Newtonian Mechanics/Forces?

Newtonian Mechanics, also known as Classical Mechanics, is a branch of physics that describes the motion of macroscopic objects using the laws of motion and gravitation developed by Sir Isaac Newton in the 17th century. It is the foundation of modern physics and is used to study the behavior of objects under the influence of forces.

What are the three laws of motion in Newtonian Mechanics?

The three laws of motion in Newtonian Mechanics are:
- The Law of Inertia: An object at rest will remain at rest, and an object in motion will stay in motion at a constant velocity unless acted upon by an external force.
- The Law of Acceleration: The acceleration of an object is directly proportional to the applied force and inversely proportional to its mass.
- The Law of Action and Reaction: For every action, there is an equal and opposite reaction.

How do forces affect the motion of objects?

Forces can change the motion of an object in two ways:
- They can change the speed of an object by causing it to accelerate or decelerate.
- They can change the direction of an object by causing it to change its velocity.
The net force acting on an object determines the resulting motion according to Newton's Second Law of Motion.

What is the difference between mass and weight in Newtonian Mechanics?

Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity acting on an object. In Newtonian Mechanics, mass is considered to be a constant, while weight can vary depending on the strength of the gravitational field.

What are some real-life applications of Newtonian Mechanics?

Newtonian Mechanics is used in many fields, including engineering, astronomy, and sports. Some common examples of its applications include:
- Calculating the trajectory of a rocket or satellite.
- Designing structures and buildings to withstand external forces.
- Understanding the motion of planets and other celestial bodies.
- Analyzing the forces involved in sports such as throwing, kicking, and jumping.

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