Steep safety ramps are built beside mountain highway to enable vehichles with fedective brakes to stop safely. a truck enters a
1000 ft ramps at a high speed vo and travels 600ft in 7 s at constant deceleration before its speed is reduced to uo/2. Assuming the same constant deceleration.
Determine:
a. The additional time required for the truck to stop.
b. The additional distance traveled by the truck.
Determine:
a. The additional time required for the truck to stop.
b. The additional distance traveled by the truck.
1 answer:
Answer:
a. 6 seconds
b. 180 feet
Explanation:
Images attached to show working.
a. You have the position of the truck so you integrate twice. Use the formula and plug in the time t = 7 sec. Check out uniform acceleration. The time at which the truck's velocity is zero is when it stops.
b. Determine the initial speed. Plug in the time calculated in the previous step. From this we can observe that the truck comes to a stop before the end of the ramp.
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Answer:
the temperature T at which the treatment is carried is out is 1274.24 K
Explanation:
Fick's second Law posits that the rate of change of concentration of diffusing species is directly proportional to the second derivative of the concentration.
Using the expression of the Fick's second Law:
where;
= initial concentration
= the depth of the concentration
= surface concentration
= Gaussian error function.
Let variable z be used for the expression of the Gaussian error function.
Then, from the above equation: replacing with 0.35 ;
with 0.2 and
with 1.0; we have:
erf (z) = 0.8125
we obtain the error function value close to 0.8125 from the error function table and we did the interpolation to obtain the exact value of variable corresponding to 0.8125.
The table below shows the tabular form of the error function value close to 0.8125 .
Value for z Value for erf (z)
0.9 0.797
z 0.8125
0.950 0.8209
From above; we can find the value of variable corresponding to the error function 0.8125 .
i.e
z = 0.932
However, the temperature dependence relation for the diffusion coefficient D can be expressed as:
where;
z = 0.932
x = 3.5 mm = 0.0035 m
t = 50 h = 180000 sec
D =
Finally, the temperature T at which the treatment is carried is out is calculated as:
From the table ‘Diffusion data’, we obtain the values of temperature-independent pre exponential and activation energy for diffusion of carbon in FCC Fe.
Replacing all values needed for the above equation; we have:
-13.977 = -17,810/T
T = -17,810/ - 13.977
T = 1274.24 K
Hence, the temperature T at which the treatment is carried is out is 1274.24 K
Answer:
See below
Explanation:
<u>Check One-Sample T-Interval Conditions</u>
Random Sample? √
Sample Size ≥30? √
Independent? √
Population Standard Deviation Unknown? √
<u>One-Sample T-Interval Information</u>
- Formula -->
- Sample Mean -->
- Critical Value -->
(given
degrees of freedom at a 95% confidence level)
- Sample Size -->
- Sample Standard Deviation -->
<u>Problem 1</u>
The critical t-value, as mentioned previously, would be , making the 95% confidence interval equal to
This interval suggests that we are 95% confident that the true mean levels of lead in soil are between 381.5819 and 398.9181 parts per million (ppm), which satisfies the EPA's regulated maximum of 400 ppm.