Lecture 3: Introduction to Physics 101. Chapter 1 : Scalars and Vectors (1.5) Chapter 2: Distance and Displacement, Speed and Velocity (2.1,2.2). correct. Conversion of Units – Example. A Cheetah’s acceleration when hunting can be a=6.1 m/s 2
Chapter 1 :
Definition of sine, cosine and tangent:
Sin q = ho/h
Cos q = ha/h
Tan q = ho/ha
opposite to angle
Pythagorean Theorem: h2 = ho2 + ha2
Any Triangle: Laws of Cosines, Sines (see E.2)
The silhouette of a Christmas tree is an isosceles
The angle at the top of the triangle is 30 degrees,
and the base measures 2 meters across.
How tall is the tree (in meters) ?
Scalars are quantities which are completely
specified by their magnitude (single number+unit).
There are physical quantities which are not
completely specified by their magnitude.
Displacement is the difference between final and initial
position of a body.
Assume a person is at an initial position A. What do you have to
specify to completely pin down the person’s final
position with respect to A ?
To be able to describe both magnitude and direction of a
physical quantity we use vectors.
Vectors are graphically represented by arrows:
R = A+B = (Ax+Bx) x + (Ay+By) y
I strongly suggest that you try the
example problems in the textbook.
If you have trouble with any of them, please
go to office hours for help!