Calculate Fnet & Direction: 2 Cars & Big Airplane

  • Thread starter homevolend
  • Start date
In summary, the two cars at the airport are trying to pull an airplane with two steel cables. Car 1 has a force of 51000 Newtons at 30 degrees, while car 2 has a force of 68000 Newtons at 60 degrees. However, the person does not know how to find Fy (the direction of the net force) and the magnitude of Fnet.
  • #1
homevolend
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Homework Statement



2 cars at an airport are pulling a big airplane with two steel cables. Car 1 pulls with force 51000N at 30° angle. Car 2 pulls with force 68000N at 60° angle, both pull in forward direction. find fnet and direction

[PLAIN]http://img16.imageshack.us/img16/8035/planek.png [Broken]



The Attempt at a Solution




Well we need to finding F1x F1y and F2x F2y.

I found Fx already by doing:


F1x=51000cos30
F1x=44167.3N

F2x=68000cos60
F2x=34000N

So Fx= F1x+f2x
Fx=78167.3 N


But I don't know how to find Fy and the direction, but I know I need fy first before I find the direction. I know for Fy you use the sin instead of cos but I don't know how to find Fy.. need some help please.


thanks!
 
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  • #2
Its just simple trig and breaking down the force into the components. You cannot add vectors directly, but you can add there components together.

Sum of forces in Y direction = F1sin(30) - F2sin(60) //the minus is due to opposite direction
 
  • #3
Ok I did this but does y turn out negative that's what I got.. thanks for the help. I know how to find direction and fnet now, just not sure on the negative part.

thanks
 
  • #4
yes, you get a negative answer but that negative is there just to show direction. So in this case the net force in Y is directed downward.

So Fy = -3.3*10^4 (j) j = y direction

Fx = -8.81 * 10^4 (i) i = x direction (I put the negative since the forces are pulling to the left, negative x direction)Adding the components will give you a vector describing the net force

Fnet = Fx + Fy = -8.81*10^4 (i)-3.3*10^4 (j)

Looking at the picture, doesn't that vector make sense? You have 68000 Newtons pulling downward at 60 degrees, there for the force has to be downward. X direction is easy, obviously the forces is to the left

To find the magnitude of Fnet you simple take the square root of the sum of the squared components. Its Pythagorean theorem basically
 
  • #5




To find Fy, we can use the same method as we did for Fx. Using the sine function, we can find the y-component of the forces. So, F1y=51000sin30=25500N and F2y=68000sin60=58800N. Now, to find the net force, we can use the Pythagorean theorem to find the magnitude of the net force: Fnet=√(Fx^2+Fy^2)=√(78167.3^2+58800^2)=97690N. The direction of the net force can be found by using the inverse tangent function: tan^-1(Fy/Fx)=tan^-1(58800/78167.3)=37.4°. Therefore, the net force on the airplane is 97690N at an angle of 37.4° above the horizontal. This direction can also be described as being towards the upper right direction.
 

1. How do you calculate the net force and direction of two cars and a big airplane?

To calculate the net force and direction of two cars and a big airplane, you first need to determine the individual forces acting on each object. This can include forces such as gravity, friction, and applied forces. Once you have identified all the forces, you can use vector addition to find the net force and direction. This involves adding all the forces together, taking into account their magnitudes and directions.

2. What is the significance of calculating the net force and direction of multiple objects?

Calculating the net force and direction of multiple objects is important in understanding how they will move and interact with each other. It allows us to predict the overall motion of the objects and determine whether they will accelerate, decelerate, or maintain a constant velocity.

3. Can the net force and direction of multiple objects ever be zero?

Yes, the net force and direction of multiple objects can be zero. This means that all the forces acting on the objects are balanced and there is no overall acceleration. The objects will either remain at rest or continue moving at a constant velocity.

4. How does mass affect the net force and direction of multiple objects?

The mass of an object does not directly affect the net force and direction of multiple objects. However, it does impact the acceleration of the objects. Objects with a larger mass will require a greater net force to accelerate compared to objects with a smaller mass.

5. What is the role of direction in calculating the net force of multiple objects?

Direction is a crucial factor in calculating the net force of multiple objects. Forces act in specific directions and can either be in the same or opposite direction. When calculating the net force, it is important to take into account the direction of each force and how they will interact with each other.

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