velocity 問題

1.velovity 分為average 同instaneous only?

2.initial velocity belongs to instaneous or average velocity?

3. the velocity of the car is +50ms^-1, velocity 係邊種?

1 個解答

  • J
    Lv 5
    1 十年前

    Average velocity is obtained by

    final displacement / time taken

    however, the actual velocity may be changing within that period of time.

    for example,

    a racer takes part in a 400 m race. After finishing the race (400 m, a cycle), his final displacement is zero, so his average velocity is zero.

    however, the racer of course have velocity at different time!!

    that velcoity which at a specific time is called instantaneous velocity.

    instantaneously velocity can be found by using equations of motion:

    v = u + at

    v^2 - u^2 = 2as

    s = ut + (1/2)at^2

    s = (u + v)t/2

    2007-10-31 01:16:24 補充:

    initial velocity=its velocity at the begining, i.e. with a specific time, so it is instantaneous velocity.for velocity is 50, if its velcoity unchange, aver. velocity=instantaneous velocity=50if it accelerates, then 50 is only the initial velocity, so is instantaneous velocity.