What is engine knock? What cause the engine knock problem?
1 answer:
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The image is missing, so i have attached it.
Answer:
A) P = 65.11 KN
B) Q = 30 KN
Explanation:
We are given;
The end reaction of the beam; F = 100KN
Coefficient of static friction between two steel surfaces;μ_ss = 0.3
Coefficient of static friction between steel and concrete;μ_sc = 0.6
So, F1 = μ_ss•F =0.3 x 100 = 30 KN
F2 = μ_ss•N_EF = 0.3N_EF
From the screen shot, we see that the angle is 12°
Sum of forces in the Y-direction gives;
F2•sin12 - N_EF•cos12 + 100 = 0
Rearranging gives;
N_EF•cos12 - F2•sin12 = 100
Let's put 0.3N_EF for F2 to give;
N_EF•cos12 - 0.3N_EF•sin12 = 100
Thus;
N_EF(0.9158) - 0.1247 = 100
N_EF(0.9781) = 100 + 0.1247
N_EF = 100.1247/0.9158
N_EF = 109.33 KN
Thus, F2 = 0.3N_EF = 0.3 x 109.33 = 32.8 KN
Wedge will move if;
P = (F1 + F2cos12 + N_EFsin12)
Thus;
P = 10 + (32.8 x 0.9781) + (109.33 x 0.2079)
P ≥ 65.11 KN
B) For static equilibrium, Q = F1
Thus, Q = 30 KN
Answer:
Explanation:
Notation
In order to do the dimensional analysis we need to take in count that we need to conditions:
a) The energy A is released in a small place
b) The shock follows a spherical pattern
We can assume that the size of the explosion r is a function of the time t, and depends of A (energy), the time (t) and the density of the air is constant .
And now we can solve the dimensional problem. We assume that L is for the distance T for the time and M for the mass.
[r]=L with r representing the radius
[A]= A represent the energy and is defined as the mass times the velocity square, and the velocity is defined as
[t]=T represent the time
represent the density.
Solution to the problem
And if we analyze the function for r we got this:
And if we replpace the formulas for each on we got:
And using algebra properties we can express this like that:
And on this case we can use the exponents to solve the values of x, y and z. We have the following system.
We can solve for x like this x=-y and replacing into quation 2 we got:
And then we can solve for x and we got:
And if we solve for z we got:
And now we can express the radius in terms of the dimensional analysis like this:
And K represent a constant in order to make the porportional relation and equality.
The problem says that we can assume the constant K=1.
And if we solve for the energy we got:
And now we can replace the values given. On this case t =0.025 s, the radius r =140 m, and the density is a constant assumed , and replacing we got:
And we can convert this into ergs we got:
And then we know that 1 g of TNT have
And we got: