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Feedback Comments on Force

by Ron Kurtus

A total of 162 comments and questions have been sent in. They are listed according to date.

You can read them to further your understanding of the subject.

List of next 10 letters




Forces Forces involved in rocket launch India
Centripetal Force Work when traveling in a circle Pakistan
Characteristics of Force Who is the father of physics? Ghana
Forces Passenger in accelerating vehicle UK
Characteristics of Force What type of force does a knife apply? Nigeria
Centrifugal Force is Not Real A real force requires acceleration Pakistan
Forces A pulling force is impossible Canada
Force and Motion How does a force come? India
Characteristics of Force How can i measure a force on a building? Nigeria
Forces Wants Newton's Third Law explained Pakistan

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First 10 letters

Forces involved in rocket launch

Topic: Forces


November 20, 2011

A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.

vinod - India



There is the force of the rocket engine pushing it upward. Then there is the inertial force resisting acceleration. There is also air resistance force and the force of gravity.

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Work when traveling in a circle

Topic: Centripetal Force


November 5, 2011

sir why work done is zero when moving in a circle? explain briefly

owais - Pakistan



Work is defined as a force overcoming a resistance times the distance traveled. The force and distance traveled are in the same line.

When the force is perpendicular to the line of motion, such as when spinning an object on a string or the effect of gravitation from the Sun on the Earth, there is no motion in line with the force. They remain at the same distance, and thus the work done is zero.

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Who is the father of physics?

Topic: Characteristics of Force


August 9, 2011

who is the father of physics?

jennifer - Ghana



Each country has had scientists and physicists who have made valuable contributions. The English-speaking countries often say that Isaac Newton was the father of physics. However, there were many good scientists before him that led the way. Other countries would claim their person was the father.

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Passenger in accelerating vehicle

Topic: Forces


July 6, 2011

Passenger who is seated in a vehicle is travelling with an acceleration 'a' . Explain the forces of the passenger who is seated in the vehicle and other observer standing outside of the car observes

- UK



The force pushing the passenger toward the seat back is F = ma, where "m" is his mass and "a" is the acceleration of the vehicle. Since the person is seated, he is not moving with respect to the vehicle. An outside observer cannot tell of any forces on the passenger, so he will simple the the passenger moving forward with the vehicle.

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What type of force does a knife apply?

Topic: Characteristics of Force


April 8, 2011

I know that a pair of scissors or shears shears by a shearing force. What about when one is using a knife to cut an object, is shearing also actually taking place here; if not, then what? Must a force, such as a shearing force or of some other forms, cause a push or pull; can't it create internal stress or something else? If it can, shouldn't that broaden our orientation of what a force is?

Thank you very much for your anticipated response.

- Nigeria



A knife is considered a wedge, which is a simple machine. When you push on a knife with a given force, the resulting pressure is force divided by the applied area. Since the knife is very sharp, the cutting area is quite small, such that the pressure can cut into a material. Then the knife acts as a wedge to push apart the sides of the material.

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A real force requires acceleration

Topic: Centrifugal Force is Not Real


April 8, 2011

Here u says centrifugal force isn't a real force Because a real force requires acceleration. How can centripetal force contain acceleration. Kindly explain.

Rahat - Pakistan



What they call a real force is what is caused by a physical push or a pull. It is like pushing on a door is a real force. It will accelerate the door.

But also, a property of matter is inertia that say matter tends to go in a straight line. If an object is caused to curve, there is the inertia force that tries to keep it going straight. That force is called a virtual force, because it is really a property of matter and not something external.

Changing directions is an acceleration and requires a force. Thus, swinging an object on a string accelerates the object by changing its direction.

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A pulling force is impossible

Topic: Forces


February 11, 2011

Mysterious Force at a Distance is nonsense.

F=mA A Pulling Force is "Impossible" !

Giant Scientific Discovery

AL - Canada



There are many examples of a force at a distance that have not been effectively explained. In some cases--like the attraction of opposite poles of the magnets--where you could say the magnetic field wraps around and pushes the magnets together, there are many others where pushing does not really make sense. However, it may be a matter of interpretation.

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How does a force come?

Topic: Force and Motion


January 22, 2011

How force will come please answer me

ningappa - India



A force is a push or a pull. You can apply a force by pushing on something. Likewise, the wind or an explosion can apply a force.

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How can i measure a force on a building?

Topic: Characteristics of Force


January 18, 2011

how can i measure a force on a story building

hamzat - Nigeria



Something has to cause the force on a building, whether it is gravity or wind or something else. That is the starting point for measuring the force.

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Wants Newton's Third Law explained

Topic: Forces


December 10, 2010

sir first of all i thanks u because u make the web then every student can gain knowledge from its .but i have some problem so i am tell u that how is a newtons discoverd its 3lw and how is its use in our daily life plz tell us about clearly concept

vijay - Pakistan



Isaac Newton was a very observant scientist, such that he knows things Andrew some sharp conclusions. But also he was helped by the work of other scientists.

Newton's Third Law is called the action-reaction law. This law is useful when you row a boat, where the action of the oar pushes the boat for word as a reaction. Also, the hot air coming out of a jet engine pushes the aircraft forward.

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