Scientists used A telescope
First, you need to calculate the resultant force:
R = m · a
= (12.3 + 5.1) · 1.5
= 26.1 N
Then, you can calculate the force of friction:
R = F - Fₐ
Fₐ = F - R
= 33 - 26.1
= 6.9 N
Now, we know that:
Fₐ = μ·m·g
Therefore we can solve for μ:
μ = <span>Fₐ/mg
= 6.9 / (17.4 · 9.8)
= 0.40
The coefficient of dynamic friction is </span>μ = <span>0.40
</span>
Answer:
394.26 m
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.8 m/s²
![v=u+at\\\Rightarrow 0=44-9.8\times t\\\Rightarrow \frac{-44}{-9.8}=t\\\Rightarrow t=4.49 \s](https://tex.z-dn.net/?f=v%3Du%2Bat%5C%5C%5CRightarrow%200%3D44-9.8%5Ctimes%20t%5C%5C%5CRightarrow%20%5Cfrac%7B-44%7D%7B-9.8%7D%3Dt%5C%5C%5CRightarrow%20t%3D4.49%20%5Cs)
![s=ut+\frac{1}{2}at^2\\\Rightarrow s=44\times 4.49+\frac{1}{2}\times -9.8\times 4.49^2\\\Rightarrow s=98.77\ m](https://tex.z-dn.net/?f=s%3Dut%2B%5Cfrac%7B1%7D%7B2%7Dat%5E2%5C%5C%5CRightarrow%20s%3D44%5Ctimes%204.49%2B%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20-9.8%5Ctimes%204.49%5E2%5C%5C%5CRightarrow%20s%3D98.77%5C%20m)
![s=ut+\frac{1}{2}at^2\\\Rightarrow 98.77=0t+\frac{1}{2}\times 9.8\times t^2\\\Rightarrow t=\sqrt{\frac{98.77\times 2}{9.8}}\\\Rightarrow t=4.49\ s](https://tex.z-dn.net/?f=s%3Dut%2B%5Cfrac%7B1%7D%7B2%7Dat%5E2%5C%5C%5CRightarrow%2098.77%3D0t%2B%5Cfrac%7B1%7D%7B2%7D%5Ctimes%209.8%5Ctimes%20t%5E2%5C%5C%5CRightarrow%20t%3D%5Csqrt%7B%5Cfrac%7B98.77%5Ctimes%202%7D%7B9.8%7D%7D%5C%5C%5CRightarrow%20t%3D4.49%5C%20s)
Total time taken by the stone to reach the ground is 4.49+4.49 = 8.97 seconds
![s=ut+\frac{1}{2}at^2\\\Rightarrow h=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{h\times 2}{9.8}}](https://tex.z-dn.net/?f=s%3Dut%2B%5Cfrac%7B1%7D%7B2%7Dat%5E2%5C%5C%5CRightarrow%20h%3D0t%2B%5Cfrac%7B1%7D%7B2%7D%5Ctimes%209.81%5Ctimes%20t%5E2%5C%5C%5CRightarrow%20t%3D%5Csqrt%7B%5Cfrac%7Bh%5Ctimes%202%7D%7B9.8%7D%7D)
The times are equal so,
![8.97=\sqrt{\frac{h\times 2}{9.8}}\\\Rightarrow h=\frac{8.97^2\times 9.8}{2}\\\Rightarrow h=394.26\ m](https://tex.z-dn.net/?f=8.97%3D%5Csqrt%7B%5Cfrac%7Bh%5Ctimes%202%7D%7B9.8%7D%7D%5C%5C%5CRightarrow%20h%3D%5Cfrac%7B8.97%5E2%5Ctimes%209.8%7D%7B2%7D%5C%5C%5CRightarrow%20h%3D394.26%5C%20m)
The height is 394.26 m
A geologist is studying rock layers in an old river bed, and he finds a fossil of a fish and a horsetail rush in the same rock layer. According to the law of faunal and floral succession, the geologist can assume that the rock containing the fossils may date back as far as the <span>Devonian period</span>.
Answer:
28.6 ohm
Explanation:
there is a 3rd resistor in series. voltage drop across the resistors will be equal to 60v
7*.2+7*.2 +.2x = 60
2.8+.2x = 60
.2x = 57.2
x = 28.6