Linear Kinetics of human movements.
Law of inertia
Mechanical behavior of bodies in contact
(friction, momentum, impulse)
Work, power and energy relationships
• Work
• Power
• Energy
Scalars and Vectors
Scalars
✓ Physical quantities having magnitude only
✓ Scalar quantities do not need direction for their description.
Examples
1.
2.
3.
4.
5.
6.
Work
Energy
Volume
Time
Speed
Temperature
7. Viscosity
8. Density
9. Power
10. Mass
11. Distance, etc
Scalars and Vectors
Vectors
✓ Having both magnitude and direction.
✓ We can't specify a vector quantity without mention of direction.
✓ Vector quantities are expressed by using bold letters with arrow sign such as:
Examples
Velocity
Acceleration
Force
Momentum
Torque
Displacement
Weight
Angular momentum etc.
Check Your Understanding
1. To test your understanding of this distinction, consider the following quantities listed below. Categorize
each quantity as being either a vector or a scalar.
Quantity
Category
a. 5 m
Scalar
b. 30 m/sec, East
Vector
c. 5 mi., North
Vector
d. 20 degrees Celsius
Scalar
e. 256 bytes
Scalar
f. 4000 Calories
Scalar
Force
Force
✓ Force is that which changes or tends to change the state of rest or of uniform motion
of body.
✓ Force is a vector quantity so it requires both magnitude and direction to be specified.
✓ The symbol for force is F.
✓ Unit of force is Newton (N) as per S.I system
✓ A force is a straight-line push or pull
Vectors addition and subtraction
✓ A directed line segment might be called an arrow.
✓ The arrowhead is the head of the directed line segment (or vector) and the
opposite end is the tail.
Vectors addition and subtraction
Vector Addition
✓ if two vectors A and B are to be added, the sum, A + B, may be obtained by connecting the vectors ‘‘head to
tail’’ ,
✓ Then constructing a vector from the tail of the first (A) to the head of the second (B) as in Figure.
✓ The sum (resultant) is the constructed vector.
Vectors addition and subtraction
Vector Addition
Vectors addition and subtraction
Vectors addition and subtraction
Vector Subtraction
✓ The subtraction of a vector is defined as the addition of the corresponding negative vector.
✓ Thus, the vector P – Q representing the difference between the vectors P and Q is obtained by adding to P the negative
vector – Q. Thus
P – Q = P + (- Q)