Mechanical Engineering - Strength of Materials - Discussion
Discussion Forum : Strength of Materials - Section 1 (Q.No. 8)
8.
Two shafts 'A' and 'B' transmit the same power. The speed of shaft 'A' is 250 r.p.m. and that of shaft 'B' is 300 r.p.m. The shaft 'B' has the greater diameter.
Discussion:
52 comments Page 3 of 6.
Naga Raju said:
9 years ago
P=2πNT/60.
For same power of two shafts NT=CON,
N=1/T>>>N=1/F. R>>> N1/R.
Here N1<N2 hence R1>R2.
But here it is given B has larger diameter.
Hence it is false statement.
For same power of two shafts NT=CON,
N=1/T>>>N=1/F. R>>> N1/R.
Here N1<N2 hence R1>R2.
But here it is given B has larger diameter.
Hence it is false statement.
Karthik s said:
9 years ago
Da = 1.2Db,
Db = 0.833 D.
Here dia of the shaft B will be less compared to the diameter of the shaft A.
Hence the statement is false.
Db = 0.833 D.
Here dia of the shaft B will be less compared to the diameter of the shaft A.
Hence the statement is false.
Singaravelan said:
8 years ago
Torque means?
Ranjit chavan said:
8 years ago
P=2 * 3.14 * N * T/60.
Where T=p * R/2.
i.e. 'p' is directly proportional to R.
Where T=p * R/2.
i.e. 'p' is directly proportional to R.
Kishan P said:
8 years ago
As Rpm increasing, torque in reduces. As torque reduce the maximum shear stress at the outer most fibre will reduce.
As it's having less shear stress, it required smaller diameter.
Hence when Rpm increasing, the diameter will be smaller When compared to a member having lower Rpm.
As it's having less shear stress, it required smaller diameter.
Hence when Rpm increasing, the diameter will be smaller When compared to a member having lower Rpm.
Govind kumar said:
8 years ago
If dia of shaft is small then it's rotation is more than the larger dia of shaft.
Paresh said:
1 decade ago
The torque relation can be obtained from above relation, but not the diameter because, if dia is smaller (as per answer, since torque is less) than even a larger diameter (than dia of shaft A) will be able to sustain that amount of torque.
Though the ' Minimum diameter ' of B will be less than that of A.
Though the ' Minimum diameter ' of B will be less than that of A.
Abin baby said:
1 decade ago
Speed of the shaft have no relation to its diameter.
Barath said:
1 decade ago
The power transmitted by the shaft is directly proportional to speed where as the torque is inversely proportional so torque reduces with speed. While designing we take smaller dia for the shaft which has to transmit lesser torque. Remember the formula P = 2*3.14*N*T/60000 KW.
Suresh said:
1 decade ago
If size of shaft increases then speed decreases.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers