Some runners train with parachutes that trail behind them to provide a large drag force. These parachutes are designed to have a large drag

Question

Some runners train with parachutes that trail behind them to provide a large drag force. These parachutes are designed to have a large drag coefficient. One model expands to a square 1.8 mm on a side, with a drag coefficient of 1.4. A runner completes a 240 mm run at 6.0 m/s with this chute trailing behind.

Required:
How much thermal energy is added to the air by the drag force?

in progress 0
Thiên Di 3 years 2021-07-25T18:30:34+00:00 1 Answers 97 views 0

Answers ( )

  1. thucuc
    0
    2021-07-25T18:32:32+00:00
    Reply

    Answer:

    by the drag force, 2.4004512 × 10⁻⁵ J is added to the air.

    Explanation:

    Given the data in the question;

    drag coefficient of Cd = 1.4

    speed v = 6.0 m/s

    One model expands to a square 1.8 mm on a side

    Area A = 1.8 × 1.8 = 3.24 mm² = 3.24 × 10⁻⁶ m²

    distance travelled s = 240 mm = 0.24 m

    we know that; density of air e = 1.225 kg/m³

    Now,

    Dragging force F_D = ( Cd × e × v² × A  ) / 2

    thermal energy = F_D × s

    so

    thermal energy = ( 1.4 × 1.225  × (6)² × (3.24 × 10⁻⁶) × 0.24  ) / 2

    thermal energy = ( 4.8009024 × 10⁻⁵ ) / 2

    thermal energy = 2.4004512 × 10⁻⁵ J

    Therefore,  by the drag force, 2.4004512 × 10⁻⁵ J is added to the air.

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )