Physics lab report calculating resultant forces -- help please

• DanchoSuper
In summary, the lab demonstrates how the forces acting on an object change as the angle between the object and the forces increases.
DanchoSuper
Homework Statement
I need to finish physics lab report. I tried doing it and teacher said that i have a lot of mistakes
Relevant Equations
Fx=Fcosa
Fy=Fsina
i have attached my attempt above i have sent it to my teacher and he said i should fix the mistakes and resend it

Attachments

• c0922affc28039788ac4648839fb1060 (1).docx
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• 34.png
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Welcome to PhysicsForums.

It's a bit hard to follow all of that. Could you please describe in words what the experiment is all about, how you did it, and what your results were? It's a bit hard to tell the difference between what are the questions and what parts are your work/answers. Thanks.

We didn't do the experiment because we're having online classes. Teacher said that the results are already given and we just need to complete it.

It's really hard to explain because I was taught Physics in russian previously for 4 years starting from 7th grade to 10th grade. But starting from this year we are taught Physics in English.

DanchoSuper said:
It's really hard to explain because I was taught Physics in russian previously for 4 years starting from 7th grade to 10th grade. But starting from this year we are taught Physics in English.
maybe you can upload a picture of the description of the experiment/question if you are having trouble explaining it?

I think it's about vectors and there are two forces and we have to find the resultant vector

DanchoSuper said:
I think it's about vectors and there are two forces and we have to find the resultant vector
Welcome, DanchoSuper!

What do you know about that?
What is that you don't understand?

http://hyperphysics.phy-astr.gsu.edu/hbase/vect.html#vec1

In order to keep the weight suspended in the air, forces F1 and F2, pointing up at certain angle (the V shape of the fish scales between both vertical supports) must compensate for Fg pointing vertically down.
The vectorial addition of F1 and F2 equals a ficticious force pointing straight up, which magnitude is exactly the same as Fg, but of opposite sign (oposite direction).

I can't see it well enough (sorry, I am old and half blind), but I believe that you have incorrectly represented the directions of vectors F1 and F2: they should look like a ∨ (heads up/tails down) instead.

The steps indicated in the lab should show you how the values of F1and F2 become greater and greater rapidly as the angle of the V-shape increases (as you separate both vertical supports from each other).

Last edited:
Hamiltonian and berkeman
So how to find the resultant force

DanchoSuper said:
So how to find the resultant force
You use the relevant equations that you showed in your first post.
After measuring F1 and F2 for each angle, you calculate F1x, F1y, F2x and F2y.
Then, you do the vector additions of F1y + F2y, as shown in above link.

1. What is a resultant force?

A resultant force is the single force that represents the combined effect of all forces acting on an object. It is the net force that causes an object to accelerate in a certain direction.

2. How do you calculate resultant forces?

To calculate resultant forces, you need to first determine the individual forces acting on an object and their respective magnitudes and directions. Then, use vector addition to find the sum of all the forces, taking into account their direction and magnitude. The resultant force will be the final vector obtained from this addition.

3. What is the difference between a scalar and a vector quantity?

A scalar quantity is a physical quantity that has only magnitude and no direction, such as mass or temperature. A vector quantity, on the other hand, has both magnitude and direction, such as force or velocity.

4. How do you use trigonometry to calculate resultant forces?

Trigonometry can be used to calculate resultant forces by breaking down the forces into their horizontal and vertical components. Then, using trigonometric functions such as sine, cosine, and tangent, you can determine the magnitude and direction of the resultant force.

5. What are some common sources of error when calculating resultant forces in a physics lab?

Some common sources of error when calculating resultant forces include inaccurate measurements, not accounting for all forces acting on an object, and not considering the effects of friction or air resistance. It is important to carefully measure and record all values and to take into account all relevant forces to minimize error in calculations.

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