Need help on difficult Newton's First Law Question

In summary, the conversation involves a person apologizing for posting in the wrong thread and asking if they can move it to the correct one. They also ask for help with a physics problem involving Batman and Robin, and later provide their own solution.
  • #1
BinaryFinary
4
0
*Just noticed that I posted in the wrong thread. Sorry about that is there any way I can move it to the right thread?*

I have a difficult question and any help would be greatly appreciated. Here it is:
To keep Robin from being captured, Batman tosses him out a third storey window, knowing that 17.0 m rope hangs slack between hooks of equal height on adjacent buildings 13.0 m apart. Robin grabs the rope and hangs on a point 5.0 m from one end. Assuming that Robin's mass is 45.0 kg and the rope withstands the initial impulse, what is the tension in each part of the rope when equilibrium is established.

Ok we know fnet is 0. Therefore the sums of the forces vertically and the horizontally must equal 0. In this problem we have mass but we don't have acceleration of the force applied by Robin (variable is a) or the acceleration of the tension (variable is b). We don't have the angle of the tension (variable @) and we don't have the Force applied horizontally by Robin (Fa) or the Tension in the rope. We do have the force of gravity however (mg, 45*9.8 = 441N). I assume that :
Horizontally
fnet = Fa - Tcos@ (Horizontal component of tension)
Tcos@ = Fa
Tcos@ = ma
T = 45a / cos@

Vertically
fnet = Fg - Tsin@ (Vertical component of tension)
Tsin@ = Fg
Tsin@ = mg
T = 441N/sin@

Substitution:
45a/cos@ = 441/sin@
45asin@ = 441cos@
45asin@/cos@ = 441
45atan@ = 441
tan@ = 441/45a
@ = tan-1(441/45a)

That will give you angle if you can get a. I believe there is a way to get a from using the values given in the question (17m, 13m, 5m) or if not then there should be a way to get @ from the values given and then solve for a instead of @. Substitute @ back into one of the T equations to get T. As I said before any help would be greatly appreciated.
 
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  • #2
Nevermind, I figured out the process to find the answer.
 
  • #3


Hi there, I'm not sure if you're aware, but you have posted this question in the wrong thread. This thread is for general discussions and not for specific homework or problem-solving help. It would be best to post this question in a thread specifically dedicated to physics or Newton's First Law.

As for your question, I understand that it can be quite challenging. My suggestion would be to break down the problem into smaller parts and use the given information to solve for the unknown variables. For example, you can use the distance and the angle to find the length of the rope using trigonometric functions. Then, you can use that length and the given mass to find the tension in the rope using the equation T=ma.

I hope this helps and good luck with your problem!
 

What is Newton's First Law of Motion?

Newton's First Law of Motion, also known as the Law of Inertia, states that an object will remain at rest or in a state of uniform motion unless acted upon by an external force.

How is Newton's First Law of Motion different from the Second and Third Laws?

Unlike the Second and Third Laws, which describe the effects of forces on objects, the First Law describes the behavior of an object in the absence of any external forces.

Can you give an example of Newton's First Law in action?

One example of Newton's First Law is a ball sitting on a flat, frictionless surface. The ball will remain still until a force, such as being kicked or pushed, is applied to it.

What are the key concepts to understand in order to solve a difficult Newton's First Law question?

The key concepts to understand are inertia, external forces, and uniform motion. Inertia is the tendency of an object to resist changes in its state of motion. External forces are any forces acting on the object from outside sources. Uniform motion is when an object moves at a constant speed in a straight line.

How can I use Newton's First Law to solve a problem?

To solve a problem using Newton's First Law, start by identifying the object and the forces acting on it. Then, determine if the object is in a state of rest or uniform motion. Finally, use the concept of inertia to analyze how the object will respond to the external forces.

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