Mechanics - contact forces

In summary: I mean, is the mass resting on the other disk?).In summary, a body of mass 10kg is suspended by a fixed support through a perfect wire at a vertical angle of 45°. The tension in the wire is given by the options a) 41N, b) 100N, c) 141N, and d) 241N. To find the tension, the forces in the x and y directions must be in equilibrium, and the tension must be written in component form to solve for its magnitude. The correct answer is c) 141N, but there may be some discrepancy due to rounding off numbers.
  • #1
rAz:DD
11
0

Homework Statement


f_1004m_a0abd84.jpg

A body of mass m = 10kg is suspended by a fixed support through a perfect wire. The body is resting on the vertical support to another disk, so that the thread
formed with a vertical angle α = 45 °, as shown. The tension from the wire has the value:
a. T = 41N
b. T = 100N
c. T = 141N
d. T = 241N

Homework Equations




The Attempt at a Solution

 
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  • #2
Draw a diagram of the forces acting on the mass. Since there is no motion, the forces must be in equilibrium. That means the vector sum of the forces in the x direction mus be equal to zero and similarly for the vector sum the forces in the y direction. You'll have to write the tension T in component form to do this. After you get the unknown components of T, you'll have to find its magnitude to answer the question.

By the way, you're supposed to show us your attempt at a solution.
 
  • #3
I've written Gx = G / cos a = T and got a strange result, but i realize now it was a math fail; the correct answer should be c) 141N right ?
 
  • #4
rAz:DD said:
I've written Gx = G / cos a = T and got a strange result, but i realize now it was a math fail; the correct answer should be c) 141N right ?

Well, I get T = 139N. Summing the forces in the y direction, I get

[tex] T = \frac{Mg}{cos(45)} = \frac{98.1}{\frac{1}{\sqrt{2}}} = 138.7 [/tex]

which I'd round off to 139N. I don't see a reason for the discrepancy right now.

Is the picture you gave the whole picture?
 
Last edited:

1. What are contact forces?

Contact forces, also known as mechanical forces, are those that result from the physical contact between two objects. This type of force can either be repulsive or attractive and is caused by the interaction of the molecules on the surfaces of the two objects.

2. What are the different types of contact forces?

There are several types of contact forces, including normal force, frictional force, tension force, and applied force. Normal force is the force that acts perpendicular to the surface of an object when it is in contact with another object. Frictional force is the force that opposes the motion of two objects that are in contact. Tension force is the force that is transmitted through a string, rope, or cable when it is pulled tight. Applied force is any external force that is applied to an object, causing it to accelerate or deform.

3. How do contact forces affect an object's motion?

Contact forces can either cause an object to accelerate or remain at rest, depending on the direction and magnitude of the force. For example, if an object is pushed or pulled in a certain direction, it will accelerate in that direction due to the applied force. On the other hand, if an object is at rest and a force is applied in the opposite direction, it will remain at rest due to the equal and opposite forces acting on it.

4. What is the difference between static and kinetic friction?

Static friction is the force that prevents two objects from sliding against each other when they are not in motion. It is always equal and opposite to the applied force, thus keeping the object at rest. Kinetic friction, on the other hand, is the force that opposes the motion of two objects that are already in motion. It is usually less than static friction and depends on the nature of the surfaces in contact and the speed of the objects.

5. How can contact forces be minimized or eliminated?

Contact forces can be minimized or eliminated by reducing the surface area of contact between two objects, using lubricants to reduce friction, or by choosing materials with lower coefficients of friction. Additionally, objects can be designed to have smooth surfaces to reduce the likelihood of frictional forces. In some cases, magnetic or electrical forces can be used to hold objects in place without physical contact.

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