# Need Help- Finding the tension and Force wind using Newton's laws

• Lolagoeslala
In summary, a spider weighing 1.20 g hangs from a tree branch at an angle of 35 degrees from the vertical due to a horizontal wind. Using the equations of Fnet = Fg + Fw + Tcosθ + Tsinθ, the force of the wind on the spider and the tension in the thread were calculated to be 0.00823 N and 0.014356 N, respectively. The angle of 35 degrees was also converted to 55 degrees to determine the horizontal component of the tension. However, converting the angle was unnecessary as the same angle can be used for both vertical and horizontal components due to the geometry of the situation.
Lolagoeslala

## Homework Statement

A 1.20 g spider hangs on its thread from the branch of a tree. A horizontal win blows the spider and the tread to an angle of 35 deg from the vertical. Find the force of win on the sider and the tension in the tread.

Diagram:
http://s1176.beta.photobucket.com/user/LolaGoesLala/media/g.jpg.html

## Homework Equations

Fnet= Fg + Fw + Tcosθ + Tsinθ

## The Attempt at a Solution

Fg = mg
Fg= (0.0012 kg)(9.8 m/s^2)
Fg= 0.01176 N

Fnet = 0.01176 N + Fw + Tcos55° + Tsin55°
I got the 55° by subtracting the 35° from 90°

Vertical equilibrium:
0.01176 N = Tsin55°
0.014356 N = T

Horizontal equilibrium:
Tcos55°=Fw
(0.014356 N)(cos55°)=Fw
0.00823 N = Fw

Hi Lolagoeslala!

Yes, that looks ok.

Two points …

i] why did you convert from 35° to 55°? it's correct, but it's unnecessary, and it gives you an extra chance to make a mistake!

ii] your line "Fnet= Fg + Fw + Tcosθ + Tsinθ" is simply wrong
(but it didn't matter, because your component equations were correct, so you didn't need that line)
… you can't add components in different directions!

correct would be "Fnet = Fg + Fw + T"

or "Fnet = Fg + Fw + (Tcosθ,Tsinθ)"

tiny-tim said:
Hi Lolagoeslala!

Yes, that looks ok.

Two points …

i] why did you convert from 35° to 55°? it's correct, but it's unnecessary, and it gives you an extra chance to make a mistake!

ii] your line "Fnet= Fg + Fw + Tcosθ + Tsinθ" is simply wrong
(but it didn't matter, because your component equations were correct, so you didn't need that line)
… you can't add components in different directions!

correct would be "Fnet = Fg + Fw + T"

or "Fnet = Fg + Fw + (Tcosθ,Tsinθ)"

Oh akay by the way for your first point how you are like why did you convert to 55° from 35°
is because when i was making the FBD... i needed the angle of the horizontal. But how would you take the 35° and work with that... i have not learned how to work with angles that are like on the opposite sides.

Lolagoeslala said:
But how would you take the 35° and work with that... i have not learned how to work with angles that are like on the opposite sides.

ah, this is elementary Euclidean geometry …

if you have a letter "N", the two angles are equal (i think they're called "alternate angles") …

so the "downward" angle (35°) between the thread and the vertical wall is the same as the "upward" angle between the thread and the imaginary vertical through the spider

(the thread corresponds to the diagonal of the "N")

tiny-tim said:
ah, this is elementary Euclidean geometry …

if you have a letter "N", the two angles are equal (i think they're called "alternate angles") …

so the "downward" angle (35°) between the thread and the vertical wall is the same as the "upward" angle between the thread and the imaginary vertical through the spider

(the thread corresponds to the diagonal of the "N")

Oh i know that LOLLL :D
Thanks for reviewing my memory :D thanks for checking by the way :D

## 1. What is Newton's first law?

Newton's first law, also known as the law of inertia, states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.

## 2. How is tension defined in physics?

Tension is a force exerted by a string, rope, or other object that is pulled tight. It is a force that stretches or elongates an object, and it is always directed along the length of the object.

## 3. How do I find the tension in a system using Newton's laws?

To find the tension in a system, you must first identify all the external forces acting on the system. Then, use Newton's second law (F=ma) to calculate the net force. Finally, apply Newton's third law to determine the tension force in the system.

## 4. What factors affect the force of wind?

The force of wind is affected by several factors, including the speed and direction of the wind, the density and viscosity of the air, and the surface area and shape of the object being acted upon by the wind.

## 5. How can I calculate the force of wind using Newton's laws?

To calculate the force of wind using Newton's laws, you will need to know the mass and acceleration of the object being acted upon by the wind, as well as the direction and speed of the wind. You can then use Newton's second law (F=ma) to calculate the force of wind on the object.

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