Because the average of one measurement would yield to itself, which provides nothing new to us. We need at least two for average to be purposeful.
Answer:
86.14 meters.
Explanation:
Step one:
Given data
velocity of car = 26 m/s
the coefficient of static friction between the tires and the road
µ = 0.4 (kinetic)
Let us take g = 9.81 m/s^2
Required
The distance x = distance in m
We know that
![N = Fg = mg\\\\F_\mu = -\mu N = \mu F_g = \mu mg\\\\KE = (1/2) mv^2](https://tex.z-dn.net/?f=N%20%3D%20Fg%20%3D%20mg%5C%5C%5C%5CF_%5Cmu%20%20%3D%20-%5Cmu%20N%20%3D%20%5Cmu%20F_g%20%3D%20%5Cmu%20mg%5C%5C%5C%5CKE%20%3D%20%281%2F2%29%20mv%5E2)
W = F*x (Work is force times distance)
Step two:
Conservation of energy gives
KE = W
Substituting gives
![(1/2) mv^2 = F \mu x\\\\(1/2) mv^2 = \mu mgx\\\\mv^2 = 2 \mu mgx](https://tex.z-dn.net/?f=%281%2F2%29%20mv%5E2%20%3D%20F%20%5Cmu%20x%5C%5C%5C%5C%281%2F2%29%20mv%5E2%20%3D%20%5Cmu%20mgx%5C%5C%5C%5Cmv%5E2%20%3D%202%20%5Cmu%20mgx)
Solving for distance (x) gives
![x = mv^2 / 2 \mu mg](https://tex.z-dn.net/?f=x%20%3D%20mv%5E2%20%20%2F%202%20%5Cmu%20mg)
Simplifying
![x = v^2 / 2 \mu g](https://tex.z-dn.net/?f=x%20%3D%20v%5E2%20%2F%202%20%5Cmu%20g)
Substitute:
![x = v^2 / 2 \mu g](https://tex.z-dn.net/?f=x%20%3D%20v%5E2%20%2F%202%20%5Cmu%20g)
![x= 26^2/2*0.4*9.81](https://tex.z-dn.net/?f=x%3D%2026%5E2%2F2%2A0.4%2A9.81)
![x=676/7.848\\\\x=86.14](https://tex.z-dn.net/?f=x%3D676%2F7.848%5C%5C%5C%5Cx%3D86.14)
Therefore, the minimum braking distance is 86.14 meters.
Answer:
oil floats in water due to the fact that it is less dense. since the water is more dense, it is basically heavier, and heavier items always sink, while lighter items float, the same can be said about liquids. denser liquids will sink while less dense items will float.
Mass of methanol = 1.922g; Change in temperature = 5.14° C; Heat capacity of the bomb calorimeter + water = 8.69kJ/°C. Number of moles.