Bio Physics

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Bio Physics
2014-03-09 03:15:46
Bio Physics

Bio Physics
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  1. Chapter 1 Concepts
    • Elapsed Time (*delta t) - The time interval between two events.
    • Distance (d or *delta x) - The length of a path between two spatial positions.
    • Displacement (d or *delta x) - The vector equivalent of distance, whcih specifies the distance and direction of one point in space relative to another. It depends only on the initial and final spatial positions, and is independent of the path taken from one positoin to the other.
    • Speed (v) - A vector measure of the rate of motion. The SI unit of speed is metres per second (m/s or m s -1)
    • Velocity (v)- A vector measure of the rate of motion, which specifies both the magnitutde and direction of the rate of motion.
    • Aceeleration (a) - A measure of the rate of change of the velocity. Acceleration is a vector quantity. The SI units of acceleration are m/s2 or m s -2.
  2. Chapter 1 Equations
    (displacement) d = vavt

    *delta v = at

    vav = 1/2(vi+vf)

    d = vit+1/2at2
  3. Chapter 2 Concepts
    • mass (m) - A measure of a body's resistance to acceleration. The SI unit of mass is the kilogram (kg), which gives the ratio of the mass of an object to a standard mass.
    • force (F) - A vector quantity that produces an acceleration of a body in the direction of its application. The SI unit of force is the newton (N). 1 N = 1 kg m s-2

    net force - The vector sum of all the forces acting on a body or system.

    Newtons first law - Any object continues at rest, or at constant velocity, unless an external force acts on it.

    Newtons second law - An external force gives the object an acceleration which is proportional to the force. F = ma

    Newtons third law - For every action there is an equal and opposite reaction.

    friction force (f)

    normal force (N) - The perpendicular component of the contact force between two objects in physical contact with each other.

    action-reaction pair - Newtons third law states that for every reaction, there is an equal and opposite reaction. These two forces form an 'action-reaction' pair that are equal in magnitude and opposite in direction. An alternative name is Newton's third-law pair.

    tension force (T) - A force that tends to stretch intermolecular bonds.

    drag - The resistance an object encounters moving through a fluid/gasses.
  4. Chapter 2 Equations
    • F = ma
    • Note: if the mass of an object on which the force is applied does not change, but the force is doubled, then the acceleration of this object will also be doubled. If the applied force is not changed, but the mass of the object is doubled, then the acceleration will be halved.

    W = mg

    fmax - uN

    • f - kv2
    • Note: k = constant of proportionality, k, is determined by the shape of the object, and by the density of the air through which it is moving.

    • F - G*m1m2/r2
    • - Note: G = is a constant '6.67 x 10-11 N m2 kg-2, when entering G into the calculator, it is simply the 6.67 x 10-11 that is entered. r = distance between the centres of mass of the two bodies and m1 and m2 are the masses of the two bodies in kilograms.

    • a = Fp/(mL+mS)
    • Note: Answer is acceleration per second2 i.e. m s-2
  5. What is f, N and mg?
    N - Normal Force (i.e. perpendicular to a line or surface)

    F - The force which is parallel (Horizontal) to the surface, friction force or often just friction.

    mg - m is the mass and g is the acceleration due to gravity. This results in the weight of an object.
  6. Scalar (Magnitude) Vs. Vector
    Scalars are quantities that are fully described by a magnitude (or numerical value) alone.

    Vectors are quantities that are fully described by both a magnitude and a direction.

    • 5 m - Scalar (no direction)
    • 5 mi., North - Vector
    • 20 degrees Celsius - Scalar (no direction)
  7. What happens when you push down on a block? What forces do you get?
    You get normal and friction forces, which would then be the perpendicular (N) and parallel (f) components of a contact force equal and opposite to the total downward force.