Newton's Second Law Homework: Forces, Accelerations, Angles

In summary, the two forces F⃗ 1 and F⃗ 2 shown in (Figure 1) act on a 29.0-kg object on a frictionless tabletop. The net force on the object is F⃗ = 10.8 N and the angle between the positive x-axis and the net force is F⃗ Ra = 90 degrees. The net force on the object is F⃗ = 19 N and the angle between the positive x-axis and the net force is F⃗ Rb = 180 degrees. The magnitude of the acceleration of the object is a=0.76.
  • #1
Angelnomahou
3
0

Homework Statement


The two forces F⃗ 1 and F⃗ 2 shown in (Figure 1) act on a 29.0-kg object on a frictionless tabletop. Suppose that F1 = 10.8 N , and F2 = 19 N .

A. Determine the magnitude of the net force on the object for the diagram (a) in the figure.

B.Determine the angle between the positive x-axis and the net force F⃗ Ra on the object for the diagram (a), measured countercockwise.

C. Determine the magnitude of the acceleration of the object for the diagram (a).

D. Determine the magnitude of the net force on the object for the diagram (b) in the figure.

E. Determine the angle between the positive x-axis and the net force F⃗ Rb on the object for the diagram (b), measured countercockwise.

F. Determine the magnitude of the acceleration of the object for the diagram (b)

I've tried to solve it these way:
a=10.8+19/29
a=0.37+0.66
a=√0.372+0.662
a=0.76
And that gives me aceleration, but I've tried to solve the aceleration for the object in diagram 2 the same way and the computer says it's wrong.
I really don't have idea of how analize the rest of the problem.
 

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  • #2
Hello Angelnomahou.

You must show your own attempt at a solution (what you've tried) before any help can be offered. Helpers need to see what you've tried so that they can determine what help you require. Helpers will not do your homework for you.
 
  • #3
I don't know what I have done, I just want to understand, please, it dosent metter if no one gives me the answer, I want to learn how to solve this kind of things, I know helpers don't have to do my homework for me, can some one explain me with another similar problem?
Please, the answer doesn't matter.
 
  • #4
Try googling on forces in two dimensions. You will find quite few resources. One such source is Khan Academy on Physics with a track on forces in two dimensions. You could start at the beginning and catch up and as you learn more in class back it up by reviewing it on Khans Academy.

Here's another resource with problems to solve and audio commentary to walk you through the solution.

http://www.physicsclassroom.com/calcpad/vecforce/problems

In your problem, you need to understand that forces add like vectors. Your proposed solutions add the forces like scalar values and that won't work as you've discovered. In the part a problem, imagine you are standing at the origin with a rope around you one end is held by your friend standing to the west at say x=-10 and another friend holding the other end of the rope is standing to the south at x=0 y=-10 and both pull you toward them. What will happen?

Well, if they pull too hard, they won't be your friends much longer. If they pull with the same strength of say 10 Newtons then you will move southwest. If the friend to the west pulls you more strongly then you will move west southwest. Do you see how that works?

Now you must use vector math to do the problem and get a more exact answer.
 
  • #5
Thanks, for the link and the other pages, ther are really usefull, I will practice there now on.
You really helped me, and there are no words to express how gratefull I feel. Thank you.
 
  • #6
jedishrfu said:
Well, if they pull too hard, they won't be your friends much longer.
Epic
 

Related to Newton's Second Law Homework: Forces, Accelerations, Angles

What is Newton's Second Law?

Newton's Second Law, also known as the Law of Acceleration, states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass. In simpler terms, this means that the larger the force applied to an object, the greater its acceleration will be. And the more massive an object is, the less it will accelerate.

How do you calculate force using Newton's Second Law?

According to Newton's Second Law, force is equal to mass multiplied by acceleration (F = m * a). This means that in order to calculate force, you need to know the mass of the object and the acceleration it is experiencing.

Can Newton's Second Law be applied to objects at rest?

No, Newton's Second Law is only applicable to objects that are in motion. For objects at rest, Newton's First Law (Law of Inertia) applies, which states that an object will remain at rest or in a state of uniform motion unless acted upon by an external force.

How does the angle of force affect acceleration?

The angle of force does not affect the acceleration of an object. As long as the net force acting on the object remains the same, the acceleration will not change. However, the angle of force does affect the direction of acceleration. For example, if a force is applied at an angle to an object, the object will accelerate in the direction of the force, but also in the direction perpendicular to the force.

Can Newton's Second Law be applied to all types of motion?

Yes, Newton's Second Law can be applied to all types of motion, including linear, circular, and rotational motion. As long as there is a net force acting on an object, its acceleration can be calculated using this law.

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