help with physics?

A cyclist travels with the velocity of 6.0m/s[W] for 45 minutes. she then heads south with a speed of 4.0m/s for 30.0 minutes.

a) calculate the displacement of the cyclist from her starting point

b) determine the average velocity for the trip

3 Answers

Relevance
  • 1 year ago
    Favorite Answer

    Since the unit of the velocity is m/s, the time must be in seconds.

    t1 = 45 * 60 = 2,700 seconds

    t2 = 30 * 60 = 1,800 seconds

    d1 = 6 * 2,700 = 16,200 meters west

    d2 = 4 * 1,800 = 7,200 meters south

    Since west is perpendicular to south, the following equation is used to determine the displacement.

    d = √(d1^2 + d2^2)

    d = √(16,200^2 + 7,200^2) = √3.1428 * 10^8

    This is approximately 17,700 meters.

    The following equation is used to determine the average velocity.

    v = d ÷ t

    t = 2,700 + 1,800 = 4,500 seconds

    v = √3.1428 * 10^8 ÷ 4,500

    This is approximately 3.94 m/s. To determine the angle south of west, use the following equation.

    Tan θ = South ÷ West = 7,200 ÷ 16,200

    This is approximately 24˚.

    OR

    Tan θ = West ÷ South = 16,200 ÷ 7,200 = 2.25

    This is approximately 66˚. These two angles are complementary. It is good when you receive to answers that are the same. I hope this is helpful for you.

  • 1 year ago

    the time for going W is 45 * 60 s and the displacement in this direction is then 6 * 45 * 60 m

    ( 16200 m)

    The time going s is 30 * 60 s so the displacement in this direction is 4 * 30 * 60 m

    (7200 m)

    The MAGNITUDE of the net displacement is given by Pythagoras = sqrt( 16200^2 + 7200^2)

    ~= 17.7 km

    and the magnitude of the net velocity ( average velocity) is displacement / time

    = 17.7 * 10 ^ 3 / ( ( 45+30)*60) ~= 3.94 m/s

    The DIRECTION is found by tan ( theta) = opposite / adjacent

    theta = atan ( 7200/16200) south of West

  • 1 year ago

    well i guess the bike is still going to be there

    unless I AM THERE

Still have questions? Get your answers by asking now.