21.2 CHAPTER 21. MOTION IN ONE DIMENSION
4 3 2 1 0 -1 -2 -3 -4
x(m)reference point
F G H J3. There are 5 houses on Newton Street, A, B, C, D and E. For all cases,
assume that positions to the right are positive.
20 m 20 m 20 m 20 mA B C D E
a. Draw a frame of reference with house A as the origin and write down
the positions of houses B, C, D and E.
b. You live in house C. What is your position relative to house E?
c. What are the positions of houses A, B and D, if house B is taken as
the reference point?More practice video solutions or help at http://www.everythingscience.co.za(1.) 009g (2.) 009h (3.) 009iDisplacement and distance ESAGV
DEFINITION: Distance
Distance is the total length of the path taken in going from the initial posi-
tion,~xi, to the final position,~xf. Distance is a scalar.
Quantity: Distance (D) Unit name: metre Unit symbol: mTipThe symbol∆is read
out asdelta. ∆is
a letter of the Greek
alphabet and is used
in Mathematics and
Science to indicate a
change in a certain
quantity, or a final
value minus an initial
value. For example,
∆xmeans change in
x while ∆t means
change int.
In the simple map below you can see the path that winds because of a number of hills from
a school to a nearby shop. The path is shown by a dashed line. The initial point,~xi, is the
school and the final point,~xf, is the shop.392 Physics: Mechanics