Explanation:
1140 miliohms.
resistance = resistivity×length /area
= 0.0000000171 ohms x 100 meters / 1.5 mm^2
Answer:
vertical load = 10 kN
Modulus of elasticity = 200GPa
Yield stress on the cable = 400 MPa
Safety factor = 2.0
Explanation:
Data
let L = ![\sqrt{(1.5)^{2} + (1.5)^{2} }](https://tex.z-dn.net/?f=%5Csqrt%7B%281.5%29%5E%7B2%7D%20%2B%20%281.5%29%5E%7B2%7D%20%7D)
= 3.35 m
substituting 1.5 m for h and 3 m for the tern (a + b)
= tan⁻¹(
)
= 45⁰
substituting 1.5 for h and 3 m for (a+ b) yields:
₂ = tan⁻¹ (
)
=25.56⁰
checking all the forces, they add up to zero. This means that the system is balanced and there is no resultant force.
If you have an engine that seized from sitting for a long time, pull the spark plugs out of all the cylinders. Fill the cylinders with engine oil and let it sit for a few days. Then, try turning the engine over with a breaker bar. If it moves, you may be able to salvage the engine
Answer: downward velocity = 6.9×10^-4 cm/s
Explanation: Given that the
Diameter of the smoke = 0.05 mm = 0.05/1000 m = 5 × 10^-5 m
Where radius r = 2.5 × 10^-5 m
Density = 1200 kg/m^3
Area of a sphere = 4πr^2
A = 4 × π× (2.5 × 10^-5)^2
A = 7.8 × 10^-9 m^2
Volume V = 4/3πr^3
V = 4/3 × π × (2.5 × 10^-5)^3
V = 6.5 × 10^-14 m^3
Since density = mass/ volume
Make mass the subject of formula
Mass = density × volume
Mass = 1200 × 6.5 × 10^-14
Mass M = 7.9 × 10^-11 kg
Using the formula
V = sqrt( 2Mg/ pCA)
Where
g = 9.81 m/s^2
M = mass = 7.9 × 10^-11 kg
p = density = 1200 kg/m3
C = drag coefficient = 24
A = area = 7.8 × 10^-9m^2
V = terminal velocity
Substitute all the parameters into the formula
V = sqrt[( 2 × 7.9×10^-11 × 9.8)/(1200 × 24 × 7.8×10^-9)]
V = sqrt[ 1.54 × 10^-9/2.25×10-4]
V = 6.9×10^-6 m/s
V = 6.9 × 10^-4 cm/s
Given Information:
Initial temperature of aluminum block = 26.5°C
Heat flux = 4000 w/m²
Time = 2112 seconds
Time = 30 minutes = 30*60 = 1800 seconds
Required Information:
Rise in surface temperature = ?
Answer:
Rise in surface temperature = 8.6 °C after 2112 seconds
Rise in surface temperature = 8 °C after 30 minutes
Explanation:
The surface temperature of the aluminum block is given by
![T_{surface} = T_{initial} + \frac{q}{k} \sqrt{\frac{4\alpha t}{\pi} }](https://tex.z-dn.net/?f=T_%7Bsurface%7D%20%3D%20T_%7Binitial%7D%20%2B%20%5Cfrac%7Bq%7D%7Bk%7D%20%5Csqrt%7B%5Cfrac%7B4%5Calpha%20t%7D%7B%5Cpi%7D%20%7D)
Where q is the heat flux supplied to aluminum block, k is the conductivity of pure aluminum and α is the diffusivity of pure aluminum.
After t = 2112 sec:
![T_{surface} = 26.5 + \frac{4000}{237} \sqrt{\frac{4(9.71\times 10^{-5}) (2112)}{\pi} }\\\\T_{surface} = 26.5 + \frac{4000}{237} (0.51098)\\\\T_{surface} = 26.5 + 8.6\\\\T_{surface} = 35.1\\\\](https://tex.z-dn.net/?f=T_%7Bsurface%7D%20%3D%2026.5%20%2B%20%5Cfrac%7B4000%7D%7B237%7D%20%5Csqrt%7B%5Cfrac%7B4%289.71%5Ctimes%2010%5E%7B-5%7D%29%20%282112%29%7D%7B%5Cpi%7D%20%7D%5C%5C%5C%5CT_%7Bsurface%7D%20%3D%2026.5%20%2B%20%5Cfrac%7B4000%7D%7B237%7D%20%280.51098%29%5C%5C%5C%5CT_%7Bsurface%7D%20%3D%2026.5%20%2B%208.6%5C%5C%5C%5CT_%7Bsurface%7D%20%3D%2035.1%5C%5C%5C%5C)
The rise in the surface temperature is
Rise = 35.1 - 26.5 = 8.6 °C
Therefore, the surface temperature of the block will rise by 8.6 °C after 2112 seconds.
After t = 30 mins:
![T_{surface} = 26.5 + \frac{4000}{237} \sqrt{\frac{4(9.71\times 10^{-5}) (1800)}{\pi} }\\\\T_{surface} = 26.5 + \frac{4000}{237} (0.4717)\\\\T_{surface} = 26.5 + 7.96\\\\T_{surface} = 34.5\\\\](https://tex.z-dn.net/?f=T_%7Bsurface%7D%20%3D%2026.5%20%2B%20%5Cfrac%7B4000%7D%7B237%7D%20%5Csqrt%7B%5Cfrac%7B4%289.71%5Ctimes%2010%5E%7B-5%7D%29%20%281800%29%7D%7B%5Cpi%7D%20%7D%5C%5C%5C%5CT_%7Bsurface%7D%20%3D%2026.5%20%2B%20%5Cfrac%7B4000%7D%7B237%7D%20%280.4717%29%5C%5C%5C%5CT_%7Bsurface%7D%20%3D%2026.5%20%2B%207.96%5C%5C%5C%5CT_%7Bsurface%7D%20%3D%2034.5%5C%5C%5C%5C)
The rise in the surface temperature is
Rise = 34.5 - 26.5 = 8 °C
Therefore, the surface temperature of the block will rise by 8 °C after 30 minutes.