Please help me. This is a question based on the Laws of Motion?

Question

A clothes line hangs between two poles. No matter how tightly the line is stretched, it always sags a little in the centre. Why?

Answer 1

F = ma: Newton's second law of motion states that the net force acting on an object equals the product of the mass (m) times the acceleration (a) of the object. The direction of the force is the same as that of the acceleration.

The units used for force are Newtons (N).
The units used for mass are kilograms (kg).
The acceleration units are meters per second squared (m/sec2).

When figuring out F=ma problems, it also necessary to use the equations of motion.
1. v2=v1+at
where v is velocity (m/sec), a is acceleration (m/sec2), and
t is time in seconds.
2. v22=v12+2as
where s is the distance in meters.
3. s=so+v1t+1/2at2

Tension in a Rope: The force tension in a rope is also measured using Newton's Second Law. However, in this situation the formula for weight is needed.

F=mg
The g for gravity is substituted for a (acceleration); the acceleration due to gravity is 9.8 meters per second (m/sec).
The formula for weight can also be used in problems involving objects on ramps. For this an object's weight is divided into two different vectors. The force parallel to the ramp accelerates the object down the ramp.

Tension is a force usually associated with a rope or a cable; it is a "response" force. In other words, if one pulls on a rope, the rope "fights back" by resisting being stretched. If the rope has negligible mass, the force exerted at one end is transmitted undiminished to each adjacent piece of rope along its entire length to the other end. Note: ropes, cords, and string can only pull. They cannot push because they bend.

It is clear that no matter how much force is applied in horizontal direction, there always must be a vertical component of tension to counteract the weight. So, you may be the strongest person in the world, but you will still find it impossible to keep the rope (or clothes line) absolutely horizontal! This is some physics for you!

Please let me know if you need more help.

Answer 2

It takes very little downward force on the center of the wire to cause a strong pull inward on the poles. It kind of works like leverage. If you do the trig, the summation of the x and y components of force or tension at that point, are proportional to each other in the same ratio as the x and y distances(the components of the distance between the lowest spot of the sag to the point where the wire is attached to the pole). the upward force which may be a pound means that if that position is sagging 6 inches and is 15 feet from the edge pole, the proportional force the the edge will feel is going to be 30 lbs, 30 times as much. Now if you imagine trying to reduce the sag by tightening the wire, as the sag decreases the ration of the distance from the end(15ft) to the amount of sag will increase to infinity as the sag approaches zero. With the sag at 1 inch, the x component of the tension will be 180lbs (90 for each side) with only one pound hanging. This means that the tension required to bring the sag to zero is infinity. Im sorry i cant explain it more clearly.

Answer 3

Wow! great question! Hope the following helps a bit; Usually, the materials of the clothesline have a functional property called flexibility, which is what makes the line tie-able. This flexibility also is reinforced with a functional property called elasticity, which allows the line to stretch along the length of the line, as well as perpendicularly (sideways) to the line. In most cases, if the line is not fully extended (stretched) when being attached/tied to the anchorings at each end of the line, there should be a little sag in the middle areas of the line (from the natural pull of gravity). The best way to tell the differences in flexible-elastic products and rigid-only products, is to try and assemble a steel rod in place of the clothesline, and see how it ties to the anchors at the ends of the line (the rod will not noticeably sag in the middle up to a certain length, depending on the strength/size of the rod).

Answer 4

This is because the clothes have its own weight. There is a gravitational force acting on the clothes. So, no matter how stretch is the line, the clothes will sags a little.
and be care ful i found it www.google.com

Answer 5

If the poles are rigid enough and enough tension is applied the line there will be no sag.

Answer 6

I suggest you read up on the word CATENARY, which is the natural curve of a flexible chain or line suspended between two points. No matter how much tension it's subjected to, it forms this curve, and the tension (together with mass/unit length) and gravity, simply determines how much it sags.
P.S. It really doesn't come under Laws of Motion, - it's more Statics.

Answer 7

i do no longer think of Galileo had any 'regulations of action'. He in easy terms postulated the heliocentric concept. Kepler of path had 3 regulations. I in easy terms keep in mind 2: a million. each planet's orbit is elliptical with the solar at between the foci 2. equivalent factors are swept out in equivalent circumstances (section swept via line connecting solar to planet) 3. I forgot - seek for in Wikipedia.

Answer 8

This is because the clothes have its own weight. There is a gravitational force acting on the clothes. So, no matter how stretch is the line, the clothes will sags a little.

Answer 9

Because the wire has a definite mass and also the wire pulls on the supports which are not perfectly rigid. If the supports were perfectly rigid or if the wire is of zero mass and infinitely large strength, then the sag would be zero.

Answer 10

There will always be a downward force on the line. If the wind is blowing up, it could have enough force to equal the force of gravity and cause the line to be equal if not up.