Results 1 to 4 of 4

Math Help - acceleration, velocity problem

  1. #1
    Senior Member
    Joined
    Jan 2007
    Posts
    477

    acceleration, velocity problem

    The left ventricle of the heart accelerates blood from rest to a velocity of +22 cm/s.
    (a) If the displacement of the blood during the acceleration is +2.1 cm, determine its acceleration (in cm/s2).
    should be in cm/s2

    (b) How much time does it take for the blood to reach its final velocity?
    in seconds?

    thankyou for looking at this.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by rcmango View Post
    The left ventricle of the heart accelerates blood from rest to a velocity of +22 cm/s.
    (a) If the displacement of the blood during the acceleration is +2.1 cm, determine its acceleration (in cm/s2).
    should be in cm/s2

    (b) How much time does it take for the blood to reach its final velocity?
    in seconds?

    thankyou for looking at this.
    We have unknown acceleration a acting for unknown time t. Then:

    <br />
v(t)=at<br />

    as the blood starts from rest, and displacement:

    <br />
s(t)=at^2/2<br />

    hence substituting in the given final velocity and displacements we have:

    <br />
22=at<br />

    and

    <br />
2.1=at^2<br />

    Now you solve this pair of quations for a and t to answer the question

    RonL
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Joined
    Apr 2005
    Posts
    1,631
    Quote Originally Posted by rcmango View Post
    The left ventricle of the heart accelerates blood from rest to a velocity of +22 cm/s.
    (a) If the displacement of the blood during the acceleration is +2.1 cm, determine its acceleration (in cm/s2).
    should be in cm/s2

    (b) How much time does it take for the blood to reach its final velocity?
    in seconds?

    thankyou for looking at this.
    The acceleration is constant.

    Given:
    Vo = 0
    V final, Vf = 22 cm/sec
    distance travelled, d = 2.1 cm

    d = [(Vo +Vf)/2]*t
    2.1 = [(0 +22)/2]*t
    2.1 =11t
    t = 2.1/11 = 0.191 sec -------------answer.

    Vf = Vo +at
    22 = 0 +a(0.191)
    a = 22/0.191 = 115.2 cm/sdec/sec -------------answer.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,857
    Thanks
    321
    Awards
    1
    Quote Originally Posted by rcmango View Post
    The left ventricle of the heart accelerates blood from rest to a velocity of +22 cm/s.
    (a) If the displacement of the blood during the acceleration is +2.1 cm, determine its acceleration (in cm/s2).
    should be in cm/s2

    (b) How much time does it take for the blood to reach its final velocity?
    in seconds?

    thankyou for looking at this.
    Actually, you can get the answer to part a) directly if you use
    v^2 = v_0^2 + 2as

    -Dan
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. position, velocity, and acceleration problem
    Posted in the Calculus Forum
    Replies: 4
    Last Post: March 19th 2010, 07:33 AM
  2. Velocity/Acceleration Problem Help
    Posted in the Calculus Forum
    Replies: 5
    Last Post: November 15th 2009, 01:51 PM
  3. Acceleration Velocity problem
    Posted in the Calculus Forum
    Replies: 5
    Last Post: October 12th 2009, 08:23 AM
  4. Acceleration/velocity/Displacement problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: January 6th 2009, 04:36 PM
  5. Acceleration-Velocity Models problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 13th 2007, 03:46 AM

Search Tags


/mathhelpforum @mathhelpforum