Turn on thread page Beta
    • Thread Starter
    Offline

    14
    ReputationRep:
    Here is the Q...

    For a particle moving in a circle with uniform speed, which one of the following statements is correct?

    A) The kinetic energy of the particle is constant.

    B) The force on the particle is in the same direction as the direction of motion of the particle.

    C) The momentum of the particle is constant.

    D) The displacement of the particle is in the direction of the force.


    I was in the middle of picking either option A or B.

    I assume that the mass of the particle will always stay the same and that momentum is 'm*v', where v is uniform (constant throughout) so isn't momentum the same too

    Kinetic energy is '1/2 m v^2' and mass is again the same again with 'v' too so KE is constant.

    I found that the answer is A.

    Why is that???

    Can someone please explain! Would really appreciate it.

    Thanks.
    Offline

    13
    ReputationRep:
    It cannot be B because the force is centripetal since the particle is in circular motion.
    Offline

    3
    ReputationRep:
    The kinetic energy of a particle is a function of it's speed, not velocity (looking at it as a vector, you would use the modulus of its velocity). Particle's speed is constant, so its kinetic energy is constant.
    Edit: momentum is a function of velocity, so is not constant in circular motion.
    • Thread Starter
    Offline

    14
    ReputationRep:
    Thanks a lot man. That does answer it for me. Thanks again.
    Posted on the TSR App. Download from Apple or Google Play
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 21, 2018

University open days

  • University of Lincoln
    Mini Open Day at the Brayford Campus Undergraduate
    Wed, 19 Dec '18
  • University of East Anglia
    UEA Mini Open Day Undergraduate
    Fri, 4 Jan '19
  • Bournemouth University
    Undergraduate Mini Open Day Undergraduate
    Wed, 9 Jan '19
Poll
Were you ever put in isolation at school?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.