Results 1 to 3 of 3

Math Help - Metric Prefix Use of formulae to solve problems Please Help

  1. #1
    Newbie
    Joined
    Oct 2008
    Posts
    2

    Wink Metric Prefix Use of formulae to solve problems Please Help

    Can someone please help me, what are the answers to these problems Ive added the link to a picture with some questions that I cant answer.

    http://i38.tinypic.com/5bw8hv.jpg
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Oct 2008
    Posts
    2
    1. How far will a ball travel if a baseball thrower pitches a ball at 43 ms^-1 in 4.2s?
    One general kinematics equation for an object at uniform speed is v(speed[in m/s])=d(distance[in m])/t(time[in s]). If v=d/t, then that can be rearranged to d=vt. We're given a speed (43 ms^-1) and a time (4.2s). If we multiply the speed and the time, (43ms^-1 x 4.2s) we get 180.6 m, or with significant figures, you would have 1.8 x 10^2

    2. How long would it take to produce 150 kW with 780 J of energy?
    It is given there that Power (watts) = Energy (joules)/time (seconds)
    The metric Kilo prefix means 1000 times so 150 kW means 150 x 1000 watts which is 150,000 W.
    If P=E/t, then that rearranged to find time would be t=E/P. The Energy we know is 780 J and the Power we found is 150,000 W. 780 J/150,000W = 0.0052 Seconds.

    3. What is the net force needed to accelerate a 5800 g, 6.2 ms^-2?
    One known dynamics thing is that acceleration is both known as ms^-2 as well as NKg^-1.
    It's given that Force (Newtons) = Mass (Kg) x Acceleration (ms^-2 OR NKg^-1). We're given the mass of the objet in grams so we need to convert that to kilograms so we divide the number by 1000 giving us 5.8 kg.
    The formula given F=ma is what we need so F = 5.8kg x 6.2 NKg^-1 = 35.96 N. With significant figures, that would round to 36 N.

    I hope my first bit of advice on this forum was of help to you.

    - Jordan
    Last edited by hjelliott; October 8th 2008 at 08:29 AM. Reason: forgot signature
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2008
    Posts
    2

    Hi

    Thanxx Hjelliot your a awesome guy
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: September 1st 2010, 08:32 PM
  2. Replies: 4
    Last Post: July 5th 2010, 07:20 AM
  3. Replies: 8
    Last Post: May 13th 2009, 04:25 PM
  4. Prefix and Infix notation
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: October 20th 2008, 06:55 PM
  5. R formulae (double angle formulae) URGENT
    Posted in the Algebra Forum
    Replies: 8
    Last Post: April 10th 2008, 12:30 PM

Search Tags


/mathhelpforum @mathhelpforum