Answer:
3.15m³
Explanation:
To solve this problem, let us first find the mass of the petrol from the given dimension.
Mass = density x volume
Volume of petrol = 4.2m³
Density of petrol = 0.3kgm⁻³
Mass of petrol = 4.2 x 0.3 = 1.26kg
So;
We can now find the volume of the alcohol
Volume of alcohol =
Mass of alcohol = 1.26kg
Density of alcohol = 0.4kgm⁻³
Volume of alcohol =
= 3.15m³
<u>Answer:</u>
<em>Thunderbird is 995.157 meters behind the Mercedes</em>
<u>Explanation:</u>
It is given that all the cars were moving at a speed of 71 m/s when the driver of Thunderbird decided to take a pit stop and slows down for 250 m. She spent 5 seconds in the pit stop.
Here final velocity ![v=0 \ m/s](https://tex.z-dn.net/?f=v%3D0%20%5C%20m%2Fs)
initial velocity
distance
Distance covered in the slowing down phase = ![250 m](https://tex.z-dn.net/?f=250%20m)
![v^2-u^2=2as](https://tex.z-dn.net/?f=v%5E2-u%5E2%3D2as)
![a= \frac {(v^2-u^2)}{2s}](https://tex.z-dn.net/?f=a%3D%20%5Cfrac%20%7B%28v%5E2-u%5E2%29%7D%7B2s%7D)
![a = \frac {(0^2-71^2)}{(2 \times 250)}=-10.082 \ m/s^2](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%20%7B%280%5E2-71%5E2%29%7D%7B%282%20%5Ctimes%20250%29%7D%3D-10.082%20%5C%20m%2Fs%5E2)
![v=u+at](https://tex.z-dn.net/?f=v%3Du%2Bat)
![t= \frac {(v-u)}{a}](https://tex.z-dn.net/?f=t%3D%20%5Cfrac%20%7B%28v-u%29%7D%7Ba%7D)
![= \frac {(0-71)}{(-10.082)}=7.042 s](https://tex.z-dn.net/?f=%3D%20%5Cfrac%20%7B%280-71%29%7D%7B%28-10.082%29%7D%3D7.042%20s)
![t_1=7.042 s](https://tex.z-dn.net/?f=t_1%3D7.042%20s)
The car is in the pit stop for 5s ![t_2=5 s](https://tex.z-dn.net/?f=t_2%3D5%20s)
After restart it accelerates for 350 m to reach the earlier velocity 71 m/s
![a= \frac {(v^2-u^2)}{(2\times s)} = \frac{(71^2-0^2)}{(2 \times 370)} =6.81 \ m/s^2](https://tex.z-dn.net/?f=a%3D%20%5Cfrac%20%7B%28v%5E2-u%5E2%29%7D%7B%282%5Ctimes%20s%29%7D%20%3D%20%5Cfrac%7B%2871%5E2-0%5E2%29%7D%7B%282%20%5Ctimes%20370%29%7D%20%3D6.81%20%5C%20m%2Fs%5E2)
![v=u+at](https://tex.z-dn.net/?f=v%3Du%2Bat)
![t= \frac{(v-u)}{a}](https://tex.z-dn.net/?f=t%3D%20%5Cfrac%7B%28v-u%29%7D%7Ba%7D)
![t= \frac{(71-0)}{6.81}= 10.425 s](https://tex.z-dn.net/?f=t%3D%20%5Cfrac%7B%2871-0%29%7D%7B6.81%7D%3D%2010.425%20s)
![t_3=10.425 s](https://tex.z-dn.net/?f=t_3%3D10.425%20s)
total time= ![t_1 +t_2+t_3=7.042+5+10.425=22.467 s](https://tex.z-dn.net/?f=t_1%20%2Bt_2%2Bt_3%3D7.042%2B5%2B10.425%3D22.467%20s)
Distance covered by the Mercedes Benz during this time is given by ![s=vt=71 \times 22.467= 1595.157 m](https://tex.z-dn.net/?f=s%3Dvt%3D71%20%5Ctimes%2022.467%3D%201595.157%20m)
Distance covered by the Thunderbird during this time=![250+350=600 m](https://tex.z-dn.net/?f=250%2B350%3D600%20m)
Difference between distance covered by the Mercedes and Thunderbird
= ![1595.157-600=995.157 m](https://tex.z-dn.net/?f=1595.157-600%3D995.157%20m)
Thus the Mercedes is 995.157 m ahead of the Thunderbird.
<span>Science is orderly knowledge proven by experimentations.</span>
Answer:
A.B = -38
Explanation:
A = 2i + 9j and B = -i - 4j.
So, A.B = (2i + 9j).(-i - 4j)
= 2i.(-i) + 2i.(-4j) + 9j.(-i) + 9j.(-4j)
= -2i.i - 8i.j - 9j.i - 36j.j
since i.i = 1, j.j = 1, i.j = 0 and j.i = 0, we have
A.B = -2(1) - 8(0) - 9(0) - 36(1)
A.B = -2 - 0 - 0 - 36
A.B = -38