Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Physics question

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Junior Member
    Join Date
    Dec 2017
    Posts
    111

    Physics question

    Hey i know this is a math site but IM struggling with a not too difficult physics question, so I didn't know where else to put this if there's anyone here who's good and has knowledge of physics please help

    The qustion says

    State the nature of the unbalanced force which is responsible for the circular motion in the following:

    (i) A Simple Pendulum
    (ii)The earth moving around the sun
    (iii)Clothes rotating in a spin dryer
    (iv)A car travelling around a bend
    (v) An electron moving around the nucleus in an atom

    For the first one I have tensional force
    For the second one I have gravitational force

    But for the others I'm unsure, I was thinking wait why don't I put centrifugal force for all?

    But then i realized thats the resulting force of the motion, they want the nature of what's causing it, so for the others I'm unsure.

    If I was to guess for 4 and 5, I would say frictional force and Nuclear force but for number 3 not sure at all.

  2. #2
    Elite Member
    Join Date
    Jun 2007
    Posts
    17,620
    Quote Originally Posted by richiesmasher View Post
    Hey i know this is a math site but IM struggling with a not too difficult physics question, so I didn't know where else to put this if there's anyone here who's good and has knowledge of physics please help

    The qustion says

    State the nature of the unbalanced force which is responsible for the circular motion in the following:

    (i) A Simple Pendulum
    (ii)The earth moving around the sun
    (iii)Clothes rotating in a spin dryer ....... Normal force from the spinning dryer wall
    (iv)A car travelling around a bend
    (v) An electron moving around the nucleus in an atom

    For the first one I have tensional force
    For the second one I have gravitational force

    But for the others I'm unsure, I was thinking wait why don't I put centrifugal force for all?

    But then i realized thats the resulting force of the motion, they want the nature of what's causing it, so for the others I'm unsure.

    If I was to guess for 4 and 5, I would say frictional force and Nuclear force but for number 3 not sure at all.
    .
    “... mathematics is only the art of saying the same thing in different words” - B. Russell

  3. #3
    Junior Member
    Join Date
    Dec 2017
    Posts
    111
    Quote Originally Posted by Subhotosh Khan View Post
    .
    Oh thanks Subhotosh, yes that makes sense, the normal reaction force would be responsible indeed!

  4. #4
    Quote Originally Posted by richiesmasher View Post
    Hey i know this is a math site but IM struggling with a not too difficult physics question, so I didn't know where else to put this if there's anyone here who's good and has knowledge of physics please help

    The qustion says

    State the nature of the unbalanced force which is responsible for the circular motion in the following:

    (i) A Simple Pendulum
    (ii)The earth moving around the sun
    (iii)Clothes rotating in a spin dryer
    (iv)A car travelling around a bend
    (v) An electron moving around the nucleus in an atom

    For the first one I have tensional force
    For the second one I have gravitational force

    But for the others I'm unsure, I was thinking wait why don't I put centrifugal force for all?

    But then i realized thats the resulting force of the motion, they want the nature of what's causing it, so for the others I'm unsure.

    If I was to guess for 4 and 5, I would say frictional force and Nuclear force but for number 3 not sure at all.
    iv) friction of tyres against the road
    v) electromagnetic force

  5. #5
    Junior Member
    Join Date
    Jan 2018
    Location
    Toronto
    Posts
    140
    Quote Originally Posted by richiesmasher View Post
    But for the others I'm unsure, I was thinking wait why don't I put centrifugal force for all?
    It's actually a centripetal force for all of them (centripetal means "pointing towards the centre"). A centrifugal force (literally "centre-fleeing", or pointing away from the centre) is only apparent in the reference frame of the rotating object, which is not an inertial reference frame (i.e. one where Newton's first law is obeyed). We like to stick to inertial frames of reference (in this case meaning non-rotating frames of reference), because the laws of physics seem to be the same in all of them.

    Quote Originally Posted by richiesmasher View Post
    But then i realized thats the resulting force of the motion, they want the nature of what's causing it, so for the others I'm unsure.
    If I was to guess for 4 and 5, I would say frictional force and Nuclear force but for number 3 not sure at all.
    The force keeping the car going around the bend is indeed friction.

    The force keeping the electron bound to the nucleus is the electromagnetic force, which is the force that causes opposite electric charges to be attracted to each other. It's not the nuclear force, which is something else. In fact there are two kinds of nuclear forces, the strong nuclear force (which keeps protons and neutrons together in a nucleus), and the weak nuclear force which...something something beta decay. https://xkcd.com/1489/

  6. #6
    Quote Originally Posted by j-astron View Post
    It's actually a centripetal force for all of them (centripetal means "pointing towards the centre"). A centrifugal force (literally "centre-fleeing", or pointing away from the centre) is only apparent in the reference frame of the rotating object, which is not an inertial reference frame (i.e. one where Newton's first law is obeyed). We like to stick to inertial frames of reference (in this case meaning non-rotating frames of reference), because the laws of physics seem to be the same in all of them.



    The force keeping the car going around the bend is indeed friction.

    The force keeping the electron bound to the nucleus is the electromagnetic force, which is the force that causes opposite electric charges to be attracted to each other. It's not the nuclear force, which is something else. In fact there are two kinds of nuclear forces, the strong nuclear force (which keeps protons and neutrons together in a nucleus), and the weak nuclear force which...something something beta decay. https://xkcd.com/1489/
    Centrifugal force doesn't actually exist, it is a phantom force. It is the object trying to continue on its current vector (perpendicular to the centripetal force) which would be conservation of momentum and newtons law of continuing or at rest unless acted upon by a force. Without the centripetal force the object will keep going in the direction its going, as the centripetal force changes the vector (acceleration : change in speed and/or direction) the inertia is felt in an outward direction and the feeling of a centrifugal force

  7. #7
    Junior Member
    Join Date
    Jan 2018
    Location
    Toronto
    Posts
    140
    Quote Originally Posted by marshall10488 View Post
    Centrifugal force doesn't actually exist, it is a phantom force. It is the object trying to continue on its current vector (perpendicular to the centripetal force) which would be conservation of momentum and newtons law of continuing or at rest unless acted upon by a force. Without the centripetal force the object will keep going in the direction its going, as the centripetal force changes the vector (acceleration : change in speed and/or direction) the inertia is felt in an outward direction and the feeling of a centrifugal force
    I am aware of its nature as a fictitious force. All I was saying is that, for the observer in the rotating reference frame, it does exist. As I said before, Newton's laws are not obeyed in such reference frames, unless you invoke such forces.

  8. #8
    Quote Originally Posted by j-astron View Post
    I am aware of its nature as a fictitious force. All I was saying is that, for the observer in the rotating reference frame, it does exist. As I said before, Newton's laws are not obeyed in such reference frames, unless you invoke such forces.
    it was more richiesmasher saying to put centrifugal for all of them that was for, but a continuation of your point

  9. #9
    Elite Member stapel's Avatar
    Join Date
    Feb 2004
    Posts
    15,887

    Cool

    Quote Originally Posted by richiesmasher View Post
    Hey i know this is a math site but IM struggling with a not too difficult physics question, so I didn't know where else to put this...
    For physics questions, maybe try a physics forum...?

  10. #10
    Quote Originally Posted by richiesmasher View Post
    Hey i know this is a math site but IM struggling with a not too difficult physics question, so I didn't know where else to put this if there's anyone here who's good and has knowledge of physics please help

    The qustion says

    State the nature of the unbalanced force which is responsible for the circular motion in the following:

    (i) A Simple Pendulum
    (ii)The earth moving around the sun
    (iii)Clothes rotating in a spin dryer
    (iv)A car travelling around a bend
    (v) An electron moving around the nucleus in an atom

    For the first one I have tensional force
    For the second one I have gravitational force

    But for the others I'm unsure, I was thinking wait why don't I put centrifugal force for all?

    But then i realized thats the resulting force of the motion, they want the nature of what's causing it, so for the others I'm unsure.

    If I was to guess for 4 and 5, I would say frictional force and Nuclear force but for number 3 not sure at all.
    For number 1 I think it is the tension force, 2 gravitational force, 3 normal force, 4 static friction force, and 5 I am not sure.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •