## meera99 3 years ago what is an inertial frame of reference?

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1. calculusfunctions

@meera 99 I'm sure that you are aware of Sir Isaac Newton's first law of motion or as sometimes referred to as the law of inertia: An object at rest will remain at rest and an object in motion will continue to move at constant speed in a straight line, unless there is an unbalanced force acting on the object. Initial reference frames are basically reference frames where Newton's first law happens. @meera99 what is that you say? OH, you're wondering, what are non-inertial reference frames? Excellent question @meera99 you must be telepathic because I was just about to tell you. You see, reference frames where objects don't move in a straight line with a constant speed, but rather rotate or accelerate are non-inertial reference frames. With the exception of planetary motion. For example, our planet Earth, even though it rotates and thus not quite an inertial reference frame, is close enough that it can be considered as an inertial reference frame. The fundamental laws of Physics are the same in all inertial reference frames. In other words, the laws of gravity and motion are the same in all inertial reference frames, although they may appear different in different reference frames. By that I mean, the position and velocity of an object are different when observed in two different reference frames. @meera99 I hope I have been able to help you in some way.

2. calculusfunctions

@meera did you understand my explanation?

3. meera99

Hi @calculusfunctions thanks for d reply but i m still not quite clear. are non-inertial frames from an inertial frame of reference? would a body accelerating be an non-inertial frame of reference?? also i was told dat motion is with respect to the observer. if a body A and body B are moving at constant velocity of 10m/s and 12m/s respectively i was told dat body B was at rest with respect to body A but i don't quite understand.

4. calculusfunctions

@meera99 you should read my explanation again just to be clear. I thought I made it clear that initial reference frames and non-inertial reference frames are not the same, and I thought I also made it clear that the laws of gravity and motion are the same in all inertial reference frames, although they are different in different reference frames. For example, if you are walking inside a train toward the front of the train at a constant speed of let's say 1 m/s and the train is moving at a speed of 25 m/s with respect to the Earth, then you are walking at a speed of 26 m/s with respect to the Earth. However, with respect to the train, you are still walking at a rate of 1 m/s.

5. calculusfunctions

Do you understand now? I have to sign out now but if you need more than I will teach you when I sign back on.

6. calculusfunctions

I'd like to see what @rkrevolutionclass13 is writing before I go.

7. calculusfunctions

@meera99 do you understand now or still not?

8. rkrevolutionclass13

A frame of reference that remains at rest or moves with constant velocity with respect to other frames of reference is called 'INERTIAL FRAME OF REFERENCE'. An inertial frame of reference is actually an unaccelerated frame of reference. Newton's laws of motion are valid in all inertial frames of reference. In this frame of reference a body does not acted upon by external forces. All inertial frames of reference are equivalent for the measurement of physical phenomena. Example Our earth. A space shuttle moving with constant velocity relative to the earth. A rocket moving with constant velocity relative to the earth. for more understanding go furthere.. To say that the velocity of a frame of reference is constant is the same as saying that the frame is not accelerating. So, we could define an inertial frame of reference to be a coordinate system which is not accelerating. Such a constant velocity frame of reference is called an inertial frame because the law of inertia holds in it. That is, an object whose position is judged from this frame will tend to resist changes in its velocity; it obeys the law of inertia. An object within this frame will not spontaneously change its velocity. An object within this frame will only change its velocity if an actual non-zero net force is applied to it. There are several ways to describe an inertial frame. Here are a few descriptions: An inertial frame of reference is a frame of reference with constant velocity. An inertial frame of reference is a non-accelerating frame of reference. An inertial frame of reference is a frame of reference in which the law of inertia holds. An inertial frame of reference is a frame of reference in which Newton's laws of motion hold. In an inertial frame of reference no fictitious forces arise.

9. calculusfunctions

I am a teacher. @rkrevolutionclass13 are you also a teacher?

10. rkrevolutionclass13

ya

11. rkrevolutionclass13

i m agree with you. but i wanted to add something more.

12. calculusfunctions

@rkrevolutionclass13 of course! I figured that you were a fellow teacher.

13. calculusfunctions

Well let's see if she understands now? I have to go as I said. I can leave with assurance that she is in good hands. Thanks @rkrevolutionclass13

14. rkrevolutionclass13

thanx u too for supporting me.....

15. kunal

hii.. i have a doubt that an observer who is moving with an uniform velocity but has a constant angular acceleration will we still say that he is a non inertial observer??\

16. harishmit09

@kunal ya he is non inertial observer. if a observer or object having rotating motion (constant angular velocity or constant angular acceleration) will always a non-inertial frame.