Αποτελέσματα Αναζήτησης
This “jiggling about” by lots of molecules leads to diffusion. Individual molecules follow a random walk, due to collisions with surrounding molecules. Diffusion = many random walks by many molecules. Substance goes from region of high concentration to region of lower concentration.
Biomechanical parameters can be represented as either scalar or vector quantities. A scalar is simply represented by its magnitude. Mass, time, and length are examples of scalar quantities. A vector is generally described as having both magnitude and orientation.
includes displacement, velocity, acceleration, force, momentum, and angular momentum. Quantities with magnitude and direction are labeled vector quantities. Usually, in elemen-tary treatments, a vector is defined as a quantity having magnitude and direction. To dis-
Velocity is a measurement of the rate of change in displacement the speed in a particular direction. We use the symbol v to indicate velocity and t to indicate time. velocity = ___________ displacement time taken v = ___ Nx Nt Velocity is a vector and has the unit m s 1.
If an object moves from one position to another we say it experiences a displacement. Displacement: a vector representing a change in position. A displacement is measured in length units, so the MKS unit for displacement is the meter (m). We generally use the Greek letter capital delta (Δ) to represent a change.
Speed and velocity calculations We can write the equation for velocity in symbols: v = s t v = Δs Δt The word equation for velocity is: velocity = change in displacement time taken Note that we are using Δs to mean ‘change in displace-ment s’. The symbol Δ, Greek letter delta, means ‘change in’.
know the terms ‘displacement’, ‘velocity’, ‘acceleration’ and ‘deceleration’ for motion in a straight line. be familiar with displacement–time and velocity–time graphs. be able to express speeds in di erent systems of units. know formulae for constant velocity and constant acceleration.
