Determine the frictional resistance, Mechanical Engineering

Determine the frictional resistance:

 (i) A train having weight 400 kN is running up an inclined path of 1 in 100 at a steady speed of 54 km/hour. If the frictional resistance is 0.5% of its weight, Find out the H. P. (output) of its engine.

 (ii) If the steam is cut off whereas the train is ascending this gradient, how far it shall go up the plane before coming to rest. Determine the frictional resistance to remain constant during its travel.

Solution

Figure illustrated the idealized body of train on the gradient (∠ α) moving up the plane under the driving force P.

Frictional force F is, thus, down the plane.

F = (0.5/100) × 400 = 2 kN.

Component of weight W along with the plane is W sin α ≈ 400 ×(1/100)=4KN

Gradient or slope = tan α =1/100 , α being very small and sin α ≈ tam α.

 Therefore the driving force P = F + W sin α = 6 kN.

Velocity of train = 54 km/hr

V = 54 × 1000/3600

 = 15 m / sec.

 (i)        ∴ H. P. exerted = P × V/746     = (6000 × 15)/ 746  =120.64

 (ii)       While the steam is cut off, P = 0

Retarding force = F + W sin α

                          = 6 kN.

Retardation = a

          W = 400 kN

∴ W a /g= 6

or Retardation = 6 × 9.8/400  = 0.147 m / sec2 .

When the train comes to rest, V2 = 0

(V 2)2 = (V 1)2  - 2 a s

0 = 152 - 2 × 0.147 s

∴ Distance (s) travelled up the gradient = 765 metres.

N. B.    Part (ii) of the example may also be solved by using energy principle as follows :

W. D. against resistance = KE available with the train

∴ P × s = W V2 /2 g

∴ 6 s = 400 × 152 /2 × 9.8

or,

s = 765 metres

Posted Date: 1/29/2013 7:08:51 AM | Location : United States







Related Discussions:- Determine the frictional resistance, Assignment Help, Ask Question on Determine the frictional resistance, Get Answer, Expert's Help, Determine the frictional resistance Discussions

Write discussion on Determine the frictional resistance
Your posts are moderated
Related Questions
Q. Show the Procedure of Compute flange stresses? Compute flange stresses and the actual bolt stress using: - COLT values for gasket seating stress, ‘y' and the gasket facto

what is hartnell governor


Pole: this is the centre of finite rotation of the coupler. Relative Pole: this is the pole of coupler associated to other moving link. Accuracy Points: The points at w

Confined Space Standard Various examples of workplace exist in industrial practice where spaces are characterized by several restrictions. Such spaces are identified as: manh

Use of hartung governor

INTRODUCTION: In the previous unit, you studied about the motorcycle and its various parts and systems. In this unit, we shall learn the various aspects of Entrepreneurship Develo

#q(b) Illustrate governing mechanism of Kaplan turbine.uestion..

If Motorcycle Pulls to One Side Causes of Problem Remedy Misaligned shock Absorber Front and rear wheels are not alig

Holonic Manufacturing System Holonic manufacturing implies a highly distributive organization of the manufacturing systems. Intelligence is distributed between the individual e