# Search results

1. ### Ultimate Tensile strength of ductile materials

In case of ductile materials we know that there is a substantial difference between the ultimate tensile strength and yield strength. As long as the specimen stress is below the yield strength we need not worry about engineering stress and true stress, as they as essentially same. But when...
2. ### Doubt on Fatigue Strength S-N diagrams

A standard way of plotting an S-N (fatigue strength vs no of cycles) graph is to start off by taking a value of Sm (for N=1000) cycles and joining it to the point depicting Se(Endurance Limit). Now we commonly take Sm= 0.9Sut for steels. Now I was wandering, before you actually get to use the...
3. ### Doubt Regarding Shearing Stresses In a Beam

Lets say we have a beam which is simply supported at the two extreme ends(support conditions dont matter in my question). A concentrated transverse load is applied at the halfway point. Now lets say we take a section at x= L/3 where is L the length of the beam. Now we know that transverse shear...
4. ### Roll cage design

I am a bachelors mechanical engineering student with a decent factual knowledge about cars and how they work. But i am a novice with no experience when it comes to design. Now I (along with 3 other guys) have been assigned the task of designing the roll cage of an electric car. I did not get any...
5. ### Oscillation of cylinder attached to two springs

Oscillation of cylinder attached to two springs.... Homework Statement A solid uniform cylinder of mass m performs small oscillations due to the action of two springs attached at its topmost point. Spring have spring constant k. Find time period of these oscillations in the absence of...
6. ### Oscillations of a complicated spring block system

Homework Statement A 4kg block M in horizontal plane is attached to a sprig S1 fixed to a light rod OA of length 4m as shown in diagram(refer to attachement). The other end O of the rod is hinged to rotate in the plane about the vertical axis passing through it. A spring S2 is fixed to the mid...
7. ### Intensity and Superposition of waves

Intensity and Superposition of waves.... Homework Statement Incident wave y=Asin(ax + bt + pi/2) is reflected by an obstacle at x=0 which reudces intensity of reflected wave by 36%. Due to superposition a resulting wave consist of standing wave and travelling wave given by y= -1.6 sinax.sinbt...
8. ### Longitudinal and transverse waves

Longitudinal and transverse waves.... Homework Statement A string is stretched so that its length is increased by 1/n of its original length. The ratio of fundamental frequency of transverse vibration to that of fundamental frequency of longitudinal vibration will be? Homework Equations...
9. ### Stationary waves equations

Stationary waves.... Homework Statement Which of the following equations can form stationary waves.... 1. y=Asin(wt-kx) 2. y=Acos(wt-kx) 3. y=Asin(wt+kx) 4. y=Acos(wt+kx) Homework Equations The Attempt at a Solution Answer is 1,3 and 2,4 which is obviously correct...But why...
10. ### Wire tensions homework

Homework Statement The lengths of two wires are in the ratio 1:2, their tensions are in the ratio 1:2 and their diameters in the ratio 1:3 . The ratio of the notes they emit when sounded together by the same source is? Homework Equations The Attempt at a Solution How to do this...
11. ### Standing waves

Standing waves.... Homework Statement If two waves differ only in amplitude and are propagated in opposite directions through a medium, will they produce standing waves. Is energy transported? Homework Equations The Attempt at a Solution About the first part i think they do...
12. ### Electric field

Homework Statement A charge q is placed at point O (please refer diagram in attachment) in the cavity in a spherical uncharged conductor. Point S is outside. If q is displaced from O towards S(q still remains inside the cavity) then which of the following is correct: Electric field at S will...
13. ### Electrostatics - Finding amount of heat in a circuit

Homework Statement A solid conducting sphere of radius 'a' having a charge q is surrounded by a concentric conducting sphereical shell of inner radius 2a and outer radius 3a (please refer diagram).... Find the amount of heat produced when switch is closed .... Homework Equations...
14. ### Electric potential

Electric potential.... Homework Statement 1000 drops of same size are charged to a potential of 1V each. If they coalesce to form a single drop find its potential..... Homework Equations The Attempt at a Solution Here what potential are they talking about?...A drop of liquid...
15. ### Electric flux calculation

Homework Statement A point charge is placed at the origin. Calculate the electric flux through the open hemispherical surface :(x-a)2 +y2 + z2 = a2 x> or = a. Homework Equations The Attempt at a Solution There is no diagram but this is how i visualised the question(please refer...
16. ### ELectric field inside a cavity

Homework Statement Suppose there is a cavity inside a metallic conductor...And say a chrge q is placed inside it....Now a charge -q is induced on the inner metal surface and a chrge q appears outside.... Homework Equations The Attempt at a Solution Now i have two questions ...
17. ### Combination of cells .

Combination of cells..... Homework Statement Two cells of emf E1=6V and E2= 5V are joined in parallel with same polarity on same side, without any external load. If their internal resistances are r1=2ohm and r2= 3ohm respectively , then which of the following is true? 1. terminal PD across...
18. ### Current electricity and circuits

Current electricity..... Homework Statement In the circuit shown(please refer to attchment) only thing missing is that the battery has an internal resistance of r. Now When key K1 is closed the ammeter reads I0 whether K2 is open or closed. But when K1 is open the ammter reads I0 /2 when K2...
19. ### Voltmeter question .

Voltmeter question..... Homework Statement A student connects an Ammeter A and a Voltmeter V to measure a Resistance R as shown in attached diagram.....If the Voltmeter reads 20 V and the ammeter reads 4A then R is 1. equal to5 ohm 2. Greater than 5 ohm 3. Less than 5 ohm 4. Greater than...
20. ### Archived Simple question on current electricity

Homework Statement Please refer to the diagram(attachment).....the circuit contains two resistors in series of 25 and 15 ohm respectively and there are two batteries of emf 10 V and 5 V respectively ....Only thing missing in the diagram is that both the batteries have internal resistances of...
21. ### Electric current .

Electric current..... Homework Statement When a steady current passes through a cylindrical conductor , is there an electric field inside the conductor? Homework Equations The Attempt at a Solution How do i approach this.....? I mean i know -E.dx = dV in electrostatics......So...
22. ### WHat is impedence .?

WHat is impedence.....??? Homework Statement This is really confusing me.....In my book it is mentioned that in Ac circuits Vrms=irmsZ and Vmax=imaxZ where i and V are current and Voltage respectively......And it is also mentioned that in LCR ac circuits impedence act as ohmic resistors in dc...
23. ### Fluid mechanics and torque

Fluid mechanics and torque.... Homework Statement A square gate of size 1m*1m is hinged at its mid point. A fliud of density rho fills the space to the left of the gate. A force F is applied at the bottom of the gate towards right. Find value of F such that the gate is stationary...
24. ### Barometer reading in an elevator .

Barometer reading in an elevator..... Homework Statement A barometer kept in an elevator reads 76cm when it is at rest. If the elevator goes up with increasing speed , the reading will (a).increase (b)decrease (c)remain constant (d) become zero...... Homework Equations The...
25. ### Change in density of water

Change in density of water...... Homework Statement Calculate the approximate change in density of water in a lake at a depth of 400m below the surface. The density of water at the surface is 1030kg/m3 and bulk modulus(B) of water is 2*109..... Homework Equations rho=rho0(1/(1-dP/B))...
26. ### Reading on a weighing scale

Reading on a weighing scale.... Homework Statement Two vessels have the same base area but different shapes.The first vessel takes twice the volume of water that the second vessel requires to fill up to a particular common height. IS the force excerted by water on the base of the vessel same...
27. ### Conceptual question on Modulus of elasticity

Homework Statement Lets say a wire has Youngs modulus Y, Initial length L area A and is supporting some external load/force of magnitude F.......its extension is dl..We say that the Potential energy of wire is 1/2(YA/L)(dl2).....But i am having a problen with the energy changes...
28. ### Young's modulus question .

Young's modulus question..... Homework Statement A sphere of radius 10 cm and mass 25 kg is attached to the lower ends of a steel wire which is suspended from the ceiling of a room. the point of the support is 521 cm above the floor. When the sphere is set swinging as a simple pendulum, its...
29. ### Bulk modulus question please help

Bulk modulus question....please help Homework Statement What is the change in density of water in a lake at a depth of 400 m below the surface? The density of water at the surface is 1030 kg/m3 and bulk modulus of water is 2*109 Nm2 Homework Equations For fluid New Density= Initial...
30. ### How can stress develop on a moving uniform elastic plank

Homework Statement A uniform elastic plank moves due to a constant force F distributed uniformly over the end face. The area of the ned face is S and Young's modulus = E . What is the average strain produced in the direction of force ? Homework Equations E*strain=stress.... The...