Chapter-2 Q027 - Physics For Engineers And Scientists - Solutions

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Question 27 - Problems - Chapter 2

Problem:

Consider the automobile with the position as a function of time plotted in Fig. 2.5 (below).

The car stopped after 272m.

Car position in time

Question:

a) What is the average velocity for the interval from t=0 to t=10.0 s?

b) From t=10.0 s to t=14.3 s?

Solution:

$\bigtriangleup t_1 = 10.0 - 0 = 10.0s$

$\bigtriangleup t_2= 14.3 - 10.0 = 4.3s$

The traveled way $\bigtriangleup s_1 = 200m-0m=200m$

The traveled way $\bigtriangleup s_2 = 272m-200m=72m$

The average velocity:

$$ \overline v=\frac{\bigtriangleup s}{\bigtriangleup t} $$

In [1]:
import numpy as np
t1 = 10
t2 = 4.3
d_s1 = 200
d_s2 = 72
v1_v = d_s1/t1
v2_v = d_s2/t2
print(f'The average velocity of the first part is: {v1_v:.1f} m/s')
print(f'The average velocity of the second part is: {v2_v:.1f} m/s')
The average velocity of the first part is: 20.0 m/s
The average velocity of the second part is: 16.7 m/s

سُوۡرَةُ حٰمٓ السجدة / فُصّلَت
ثُمَّ اسْتَوَىٰ إِلَى السَّمَاءِ وَهِيَ دُخَانٌ فَقَالَ لَهَا وَلِلْأَرْضِ ائْتِيَا طَوْعًا أَوْ كَرْهًا قَالَتَا أَتَيْنَا طَائِعِينَ ﴿١١
فَقَضَاهُنَّ سَبْعَ سَمَاوَاتٍ فِي يَوْمَيْنِ وَأَوْحَىٰ فِي كُلِّ سَمَاءٍ أَمْرَهَا ۚ وَزَيَّنَّا السَّمَاءَ الدُّنْيَا بِمَصَابِيحَ وَحِفْظًا ۚ ذَٰلِكَ تَقْدِيرُ الْعَزِيزِ الْعَلِيمِ ﴿١٢


Surah Fussilat: Thereafter turned He to the heaven and it was as smoke, and said Unto it and Unto the earth: come ye twain, willingly or loth. They said: we come willingly. (11) Then He decreed them as seven heavens in two days, and revealed Unto each heaven the command thereof; and We bedecked the nether heaven with lamps and placed therein a guard. That is the ordinance of the Mighty, the Knower. (12)

De hemelen en aarde (waren) een samenhangende massa. Wij hebben ze toen van elkaar gescheiden… Wij hebben de hemel tot een beschermend dak gemaakt … en de dag en de nacht, de zon en de maan geschapen. (Koran 41 11:12)


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