Recently Active Mechanics Questions

*Image* Source: 200 Puzzling problems [1] ...

*Image* Can anyone please find the center of masses of a uniform hollow hemisphere and of a frustum like shown above? You can take any variable you like. ...

*Image* A small body 'A' is fixed to the inside of a thin rigid hoop of radius R and mass equal to that of body 'A'. The hoop rolls without slipping over a horizontal plane. At the instant when the body is at lowermost positi ...

A heavy mass m is tied through a pendulum in a railway train moving at a constant speed v. The carriage is brought to rest suddenly by a strong but uniform braking. Can the pendulum travel through 180° so that the taut reach ...

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One end of an elastic string of natural length a and force constant λ/a is fixed to a point on a smooth horizontal surface vandvthe other end is attatched to aparticle of mass m lying on the surface. the particle is pulled f ...

*Image* . A sphere is rotating between a rough wall and a smooth wedge as shown in the fig. If u is the coefficient of friction between then find the normal reaction between the wall and the sphere. ...

can toppling occur even in absence of friction??? plz explain....... ...

*Image* . A block of mass m is pushed towards a movable wedge of mass nm and height h with a velocity u. All surfaces are smooth. The minimum value of u for which the block will reach the top of the wedge is... a> √2gh b ...

*Image* spring const. = k all surfaces are smooth. u hav to find out the elongation in the spring. I have brought out 2 solutions....tell me which one is right. Soln. A : kx = mg sinθ x= mg sinθ/k Soln. B : Consider the ext ...

Does anyone remember any of the following qs which came in FTSE 09?? 1.this question was about an insect which moved with a constant velocity of a disc rotating given initial and final coordinates. We had to find omega 2. Thi ...

A uniform chain of mass m hangs from a light pulley, with unequal lengths hanging from two sides of the pulley. The force exerted by the moving chain on the pulley is ....... a> mg b> >mg c> <mg d> may be an ...

2 trans, each wid speed 50 km/h , r headed towards each other on d same track. a bird which can fly at d rate of 100 km/h flies off one train when they r 100km apart and heads directly to other train. on reaching d other trai ...

An easy one... Q.A rod is rotating about center with angular speed w. If the Young modulus of elasticity of rod is Y and length and cross sectional area is l and A respectively. Find the elongation in rod. *Image* ...

This is another problem from an online contest... (This is another of the unsolved problems.. which if not solve.. you should definitely give a good thought) Prague Physics Challenge, 2nd round Falling pen Imagine that you ar ...

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A wave pulse is passing on a string with a speed of 40cm/sec. in the negative x direction. It has the maxima at x=0 at t=0. Where is the maxima located at t=5?? ...

Consider a collection of a large no. of particles , each with speed v. the direction of velocity is randomly distributed in the collection. Show that the magnitude of the relative velocity between a pair of particles averaged ...

Laila has to cross a track of ice to reach the other side of the river to meet Majnu as soon as possible... :P Now laila has 2 ways either to skid through the first track or the 2nd one.. The image shows the vertical section ...

*Image* Figure shows a smooth track a part of which is a circle of radius R. A block of mass m is pushed against a spring constant k fixed at the left end and is then released.Find the initial compression of the spring so tha ...

A 2kg is slid along the frictionless floor with initial transverse velocity(10m/s)along k axis.Describe the motion(a) in car's frame.(b) in ground frame. What are cold welded joints(regarding friction)? Three forces are actin ...

*Image* bLOCK a OF MASS M is released from rest.No friction anywhere..It undergoes 2 completely inelastic collisions.,first with the plane and then with a block of B mass 2m. and sticks to it.A total of 21J mechanical energy ...

Two blocks A and B are kept on a rough surface of coefficient of friction u=0.1 . Block B is pulled with a constant time varying velocity v(t)=0.1t . Spring constant is k=100 N/m.Then answer the following : 1. Work done by sp ...

*Image* if the system is slightly disturbed the rod starts falling down in the direction of the block, form equations to find velocity of block at the instant it leaves contact with the ball (i have solved this one....but jus ...

The time period of physical pendullum is minimum when its length is equal to the radius of gyration about its centre of gravity ...

*Image* In the system shown in figure all surfaces are smooth. Rod is moved by ext. agent with acceleration 9m/s2 downward vertically. Force exerted by the wedge on the rod is __________ . Please show the working.... ...

*Image* The pipe has uniform cross section area.the base is removed.height of water is H I don know what i am doing wrong. :( AVa=AVb Va=Vb=v now by bernaullis theorem at point A and B Patm+ρgH+ρv2/2=Patm+ρv2/2 ρgH=0 [5] ...

In HCV vol 1 - pg no. 269 - Example 7 In the very first line of the solution, the height inside the water is calculated as 3cm*0.8 = 2.4cm. How is this calculated?? ...

How does work done depend on the frame of reference ? ...

*Image* A ball connected with a string is released at an angle 45° with the vertical. Then acceleration of the box at this instant will be (mass of the box = mass of the ball and the box is lying on a smooth surface) : a) g/ ...