Civil Engineering - Surveying - Discussion

Discussion Forum : Surveying - Section 2 (Q.No. 6)
6.
If the rate of gain of radial acceleration is 0.3 m per sec3 and full centrifugal ratio is developed. On the curve the ratio of the length of the transition curve of same radius on road and railway, is
2.828
3.828
1.828
0.828.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
26 comments Page 2 of 3.

JAY PANCHAL said:   8 years ago
Explain clearly?

Asma said:   8 years ago
Please explain it clearly.

Gurkamal Singh said:   8 years ago
Centrifugal ratio for road=1/4,
Centrifugal ratio for railway=1/8,
Centrifugal ratio(c.r.)=V^2/Rg where R is the radius and g is acc. due to gravity............Eq. 1,
and also V^2/R=Acc.rate x t where t is the time..........Eq. 2,

V^2 is directly proportional to C.R. since R and g is constant.R is constant since same radius is given for road and railway.

Therefore V is directly proportional to (C.R.)^(1/2),
Now from Eq. 2.
t=V^2/acc. rate*R ..........Eq. 3.
And we also know that L=V*t where L is length v is vel. and t is time.
Putting the value of t from Eq. 3 in above equation we will get,
L=V^3/acc. rate*R
Now L is directly proportional to V^3 since acc. rate and radius are constant for both road and railway.
And V is directly proportional to C.R.^(1/2),
hence L is directly proportional to C.R.^(3/2),
Now L1(road)=k*(1/4)^(3/2).
L2(railway)=k*(1/8)^(3/2).
Dividing L1 by L2
We get L1/L2=(sq. root of 8)=2*(sq. root of 2)=2*1.414=2.828.

Learner said:   8 years ago
I can't understand it. Please explain it.

Mk said:   9 years ago
Sir please explain this question in detail.

Mohit Kumar said:   9 years ago
Explain the question properly.

GOPI said:   9 years ago
Can you explain clearly.

Luhenba said:   9 years ago
Can anyone explain clearly please?

Sree said:   9 years ago
Can you explain clearly?

Student said:   9 years ago
For road centrifugal ratio = 1/4.
For railway = 1/8.
Centrifugal ratio = v^2/Rg.
R = radius

(v^2/r) = Acceleration rate * t.
t = time

t = L/v.
L = length.
v = velocity.

Here we get L=(v^3)/(acceleration * r).

Acceleration is given and r is same for road and railway.
So, L is directly proportional to v^3 and from centrifugal ratio = v^2/Rg.
v is directly proportional to square root of the centrifugal ratio.

From here ratio of length for road and railway;
L1/L2= (1/2)^3/(1/square root 8)^3.
= 2 * square root 2.
= 2 * 1.414.
= 2.828.


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