Chapter-2 Q026 - Physics For Engineers And Scientists - Solutions

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Question 26 - Problems - Chapter 2

Problem:

Suppose you throw a baseball straight up so that it reaches a maximum height of 8.00 m and returns 2.55 s after you throw it.

Question:

a) What is the average speed for this motion of the ball?

b) What is the average velocity?

Solution:

The average speed $v = \frac{Total Distance}{Total Time}$

The total Distance $s = 8m_{up} + 8m_{down} = 16m$

The average Velocity $\overline{v} = \frac{\bigtriangleup{s}(startposition - endposition}{Total Time}$

Startposition = 0m -and- Endposition = 0m -so- $\bigtriangleup{s}=0-0=0m$

Or Total Displacement 8m to go and 8m to return $\bigtriangleup{s}=8m+-8m=0m$

Total Time $t=2.55s$

In [1]:
import numpy as np
s = 16
d_s = 0
t = 2.55
v_speed = s / t
v_velocity = 0 / t
print(f'The speed is: {v_speed:.2f} m/s')
print(f'The velocity is: {v_velocity} m/s')
The speed is: 6.27 m/s
The velocity is: 0.0 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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