CHAPTER 21. MOTION IN ONE DIMENSION 21.6
∆~x=Area under graph
=ℓ×b
= 100 (−1)
=− 100 mThis means that Vivian has a displacement of 100 m towards her house.
Exercise 21 - 5
1. Use the graphs in Figure 21.6 to calculate each of the following:
a. Calculate Vivian’s velocity between 50 s and 100 s using thexvs.t
graph. Hint: Find the gradient of the line.
b. Calculate Vivian’s acceleration during the whole motion using thev
vs.tgraph.
c. Calculate Vivian’s displacement during the whole motion using thev
vs.tgraph.
2. Thandi takes 200 s to walk 100 m to the bus stop every morning. In the
evening Thandi takes 200 s to walk 100 m from the bus stop to her home.
a. Draw a graph of Thandi’s position as a function of time for the morn-
ing (assuming that Thandi’s home is the reference point). Use the
gradient of thexvs.tgraph to draw the graph of velocity vs. time.
Use the gradient of thevvs.tgraph to draw the graph of acceleration
vs. time.
b. Draw a graph of Thandi’s position as a function of time for the evening
(assuming that Thandi’s home is the origin). Use the gradient of the
xvs.tgraph to draw the graph of velocity vs. time. Use the gradient
of thevvs.tgraph to draw the graph of acceleration vs. time.
c. Discuss the differences between the two sets of graphs in questions 2
and 3.More practice video solutions or help at http://www.everythingscience.co.za(1.) 009t (2.) 009uPhysics: Mechanics 411