Free body diagrams and adding forces

In summary: Just use the components of the forces given in the diagram. Remember, the x and y components will change since the angles of the forces are different. So you will need to recalculate Fx and Fy for diagram B before finding the net forces and accelerations.In summary, the problem involves two free-body diagrams with forces acting on a 2.6 kg object. The task is to find the values of ax and ay, the x- and y-components of acceleration, for each diagram using F1 = 5 N and F2 = 3 N. The solution involves using sin and cos to calculate the components of the forces and then adding them to find net Fx and Fy. Finally, ax and ay can be found by
  • #1
gbedenba
23
0

Homework Statement


In each of the two free-body diagrams, the forces are acting on a 2.6 kg object. For each diagram, find the values of ax and ay, the x- and y-components of the acceleration, with F1 = 5 N and F2 = 3 N. Picture is attached.

(a) Diagram A
ax =____ m/s2
ay =____ m/s2
(b) Diagram B
ax =____ m/s2
ay =____ m/s2

Homework Equations





The Attempt at a Solution



I tried to use sin and cos. I don't think I am adding the forces up right. Help! Due today! I am getting decimal numbers... I used a = F/M.
 

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  • #2
It is always better to your calculations. We must know what mistakes you have made in adding the forces. That gives un an idea about your level of understanding.
In the first problem, you have to x and y components of 3 N force. Then find net Fx and net Fy which gives you ax and ay.
 
  • #3
For x comp. of 3N = 1.02606 y= 2.81908

My guess for F net is 2.97394...

ax = F/M 1.14382?ay = .000354 wrong
 
  • #4
Show your ay calculation.
How much significant numbers you are expexted to write in the answer?
 
  • #5
Ax : 3sin(20)=1.02606
F = -1.02606-1+5 = 2.97394 = 2.97394/2.6 = 1.14382

Ay : 3cos(20)= 2.81908
F = -2.81908 + 2.82 = 0.000922 = 0.000922/2.6 = 0.000355
 
  • #6
gbedenba said:
Ax : 3sin(20)=1.02606
F = -1.02606-1+5 = 2.97394 = 2.97394/2.6 = 1.14382

Ay : 3cos(20)= 2.81908
F = -2.81908 + 2.82 = 0.000922 = 0.000922/2.6 = 0.000355
Looks good.
 
  • #7
it says Ay is wrong.

For diagram B...how would I do it?
 
  • #8
gbedenba said:
it says Ay is wrong.
Looks right to me. Perhaps they want you to round it off to zero (which is the proper answer, given the significant digits involved).
For diagram B...how would I do it?
The same way you did A.
 

Related to Free body diagrams and adding forces

1. What is a free body diagram?

A free body diagram is a visual representation of an object or system, showing all the forces acting on it. It is used to analyze the motion of the object and determine the net force acting on it.

2. How do you draw a free body diagram?

To draw a free body diagram, you need to identify all the forces acting on the object and draw arrows to represent their magnitude and direction. It is important to label each force and use a scale to accurately represent the relative sizes of the forces.

3. What is the purpose of adding forces in a free body diagram?

The purpose of adding forces in a free body diagram is to determine the net force acting on the object. By summing up all the forces, you can determine if the object is in equilibrium (if the net force is zero) or if it is accelerating in a certain direction (if the net force is non-zero).

4. How do you add forces in a free body diagram?

To add forces in a free body diagram, you must use vector addition. This means that you need to add the magnitude and direction of each force, taking into account their direction and any angles between them. You can use trigonometry or graphical methods to accurately calculate the net force.

5. Why is it important to accurately draw and add forces in a free body diagram?

It is important to accurately draw and add forces in a free body diagram because it allows you to analyze the motion of the object and predict its behavior. By understanding the net force acting on the object, you can determine if it will remain at rest or move in a certain direction. This information is crucial in many fields of science and engineering, such as mechanics, physics, and structural analysis.

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