Extremely confusing dynamics question

In summary, the conversation discusses a problem involving a painter in a crate hanging alongside a building. The painter's weight and the force he exerts on the floor of the crate are given, and the acceleration of the system is to be determined. There is confusion about whether the system is accelerating upwards or downwards and whether the tension in the rope is equal to the normal force from the floor. Some online answers suggest that the weight of the painter can be neglected, but this is not the case. It is recommended to draw free body diagrams and use equations to solve the problem.
  • #1
SecretSnow
66
0
Hi guys, this is so confusing as there are lots of assumption needed (I think). I can't do this even though I got the answer and tried working backwards.

A painter in a crate which hangs alongside a building, weighs 1000N.When the painter pulls on the rope, the force he exerts on the floor of the crate is 450N. If the crate wieghs 250N, find the acceleration. Answer: 2.0ms^-2

Firstly, we don't know whether the system is even accelerating upwards or downwards..and I also realized that the tension exerted may be just the normal force of 450N exerted back onto the painter (since he exerts 450N on the floor) does that mean he is apparently weightless? That is quite strange though, because if we consider in terms of forces acting on the painter, then it's 450N from the floor and 450N from the rope, both acting upwards. And I'm asking this because some answers I found online say the weight of the painter can be neglected although I don't know why...pls help! I'm stuck in this one question for a long long long time...
 
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  • #2
Phrased like that, the problem statement should have some sketch attached.

The answer is right if a rope goes from the crate over some fixed anchor (at the top of the building) back to the painter.
 
  • #3
SecretSnow said:
A painter in a crate which hangs alongside a building, weighs 1000N.
Note this means the painter weighs 1000N, not painter plus crate.
we don't know whether the system is even accelerating upwards or downwards..
You shouldn't need to predict that - it will come out in the answer.
and I also realized that the tension exerted may be just the normal force of 450N exerted back onto the painter
The tension in the rope equals the normal force from the floor? Why should it?
some answers I found online say the weight of the painter can be neglected
The weight of the painter is given, and certainly cannot be neglected.
Have you drawn free body diagrams for crate and painter, including an unknown tension? What equations do you get?
 

Related to Extremely confusing dynamics question

1. What is the definition of "dynamics" in this context?

In this context, "dynamics" refers to the study of how systems change over time and the factors that influence those changes.

2. What makes this question extremely confusing?

This question is extremely confusing because it may involve complex concepts, unclear terminology, or multiple variables that are difficult to understand or analyze.

3. How can I approach solving this question?

You can approach solving this question by breaking it down into smaller, more manageable parts and identifying any key terms or variables that are crucial to understanding the dynamics at play. It may also be helpful to consult with other experts or references in the field for guidance.

4. What are some real-world examples of dynamics that might be relevant to this question?

Some examples of dynamics that could be relevant to this question include population growth, weather patterns, economic fluctuations, or the spread of diseases.

5. What are the potential implications or applications of understanding the dynamics in this question?

Understanding the dynamics in this question could have various implications or applications, such as being able to predict future outcomes, making informed decisions, or developing strategies to control or manipulate the system in question.

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