Recent questions tagged unit4

A jet airplane is travelling at $200 m/s$ The engine takes in $100\;m^3$ of air having mass $100 \;kg$ each second. The air is used to burn 5 kg fuel each second. The energy is used to compress the products of combustion and to eject them at the rear of the plane at $500 m/s$ relative to the plane. The thrust of the engine is

asked Aug 8, 2013 by meena.p

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A particle is projected vertically upward with a speed of $16 m/s$, after some time, when it again passes through point of projection, its speed is found to be $8 m/s$. It is known that the work done by air resistance is same during upward and downward motion, Then the maximum height attained by the body is ? $(g=10 m/s^2)$

asked Aug 8, 2013 by meena.p

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A body of mass 3 kg under constant force which causes a displacement $s$ in meters in it given by $s=\large\frac{1}{3}$$t^2$ work done by the force in $2$ seconds is

asked Aug 8, 2013 by meena.p

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A particle of mass m is moving in a circular path of constant radius 'r'. Such that the centripetal acceleration $a_c$ is varying with time as $a_c=k^2rt$ where R is a constant. What is the power on the particle

asked Aug 8, 2013 by meena.p

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An electron of mass $'m'$ moving with velocity $'v'$ collids head on with an atom of mass M. As a result of the collision a certain fixed amount of energy $\Delta E$ is stored internally in the atom. The minimum initial velocity possessed by the electron is

asked Aug 8, 2013 by meena.p

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Under the acting of a force P, the body can't moves up an incline from initial position $x_1=-150 mm$ to $x_2=80\;m$ where $x=0$ is the unstreched position of the spring along the incline. Find the work done by the spring

asked Aug 8, 2013 by meena.p

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A bob of pendulum of length 2 m describes an are of a circle in a vertical plane. If the lension in the cord is $2.5$ times the weight of the bob for the position shown, find the velocity of the bobs at that position.

asked Aug 7, 2013 by meena.p

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A block rests on an inclined plane. A spring is attached is a pulley and is pulled downward gradually with increasing force. $\mu $ is the coefficient of friction between block and inclined plane . Find the potential energy of the spring at the momentum when block begins to move for a force constant k of spring $[\theta= 30^{\circ}]$

asked Aug 7, 2013 by meena.p

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A uniform chain of length l and mass m is placed as shown . Find the gravitational potential of chain

asked Aug 7, 2013 by meena.p

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The given graph shows the motion of a particle of mass $10/7\; kg$ the action of an external agency with power. Its initial position is $x=0$ and initial velocity is $1 m/s$ . velocity at $x=10 m$ is (use the graph)

asked Aug 7, 2013 by meena.p

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A partical is projected along a horizontal field whose co-efficient of friction varies $\mu = \large\frac{A}{x^2}$ where x is a distance from origin in meters and A is a positive constant. The initial distance of particle is 1m from orgin and its velocity is radially outwards. The minumum initial velocity at this point so that the particle never stops is

asked Aug 7, 2013 by meena.p

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A pendulum bob of mass m carying a charge 'q' is at rest with its string making an angle $\theta$ with the vertical in a uniform horizontal electric field E. The tension in the string

asked Aug 7, 2013 by meena.p

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A block of mass $0.50\;kg$ is moving with speed of $2.00 m/s$ on a smooth surface. It strikes another mass of $1.00 kg$ at rest and they move together as a single body. The energy loss during collision is

asked Aug 7, 2013 by meena.p

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A horse pulls a wagon with a force of $360\; N$ at an angle of $60^{\circ}$ with horizontal at a speed of $10 km/hr$. The Power of the horse is

asked Aug 7, 2013 by meena.p

1 answer

An object is displaced from point $A(2m,3m,4m)$ to a point B $(1m, 2m, 3m) $ under a constant force. $\hat F=(2 \hat i+3 \hat j+4 \hat k)$. Find the work done by the force

asked Aug 7, 2013 by meena.p

1 answer

A smooth narrow tube in the form of an arc AB of a circle of center O and radius r is fixed so that A is vertically above O and OB is horizontal. Particles P and Q of mass m and 2m respectively. with a light in extensible string connecting them (length $\large\frac{\pi\;r}{2}$) are placed inside the tube with P at A and Q at B. and released from rest. Assuming that the string remains during motion, find speed of particles when P reaches B

asked Aug 7, 2013 by meena.p

1 answer

A train of mass $2.0 \times 10^5$ kg has constant speed of $20 m/s$ up a hill inclined at $\theta, (\sin \theta=\large\frac{1}{50})$ to the horizontal when the engine is working at $8.0 \times 10 ^5 $ watt. Find the resistance to the motion of the train $(g=9.8 m/s^2)$

asked Aug 7, 2013 by meena.p

1 answer

A block of mass $0.80 kg $ is attached to a cord passing through a hole in a horizontal frictionless surface. The block is originally revolving at a distance of $0.30 m$ from the hole with a speed of $0.80 m/s$ The cord is pulled from below the hole, shortening the radius of circle in which the block revolves to $0.10 m$. At this new distance the speed of block is $2.40 m/s$. How much work is done by person who pulled the cord?

asked Aug 7, 2013 by meena.p

1 answer

Two masses $m_1$ and $m_2$ connected by light spring rests on horizontal plane. The coefficient of friction between the masses and surface is $\mu$. What minimum force has to be applied in horizontal direction to the mass $m_1$ in order to shift the mass $m_2$ $ (g= 10 m/s^2)$

asked Aug 7, 2013 by meena.p

1 answer

An objecte of mass 5 kg falls from rest through a vertical distance of 20 m and reaches velocity 10 m/s. How much work is done by push of air on the object $(g=10 m/s^2)$

asked Aug 7, 2013 by meena.p

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In the arrangement as shown a mass m is released from rest with spring unstreched.What is the speed of block at equillibrium position

asked Aug 6, 2013 by meena.p

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A cyclotron is used to accelerate protons deuterons, $\alpha$- particles etc. If energy attained after acceleration by proton is E, the energy attained by $\alpha$- particle shall be

asked Aug 6, 2013 by meena.p

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The potential energy of a 1 kg mass free to move along the x-axis is given by $V_{(x)}=\bigg[\large\frac{x^4}{4}-\frac{x^2}{2}\bigg]$$J$ The total mechanical energy of the particle is $2J$ then the maximum speed is?

asked Aug 6, 2013 by meena.p

1 answer

An object of mass m is lied to a string of length l and a variable horizontal force is applied on it which is initially zero and gradually increases until the string makes an angle $\theta$ with the vertical. Work done by the force F is

asked Aug 6, 2013 by meena.p

1 answer

A particle moves with velocity $v= (5 \hat i -3 \hat j+6 \hat k) m/s$ under the influence of a constant force $\hat F=(10 \hat i+10 \hat j+20 \hat k)N$. The instantaneous power applied to the particle is

asked Aug 6, 2013 by meena.p

1 answer

A body moves a distance 10m along a straight line under the action of force $5N.$ If the work done is $25J$, the angle which the direction of motion of body is

asked Aug 6, 2013 by meena.p

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A block of mass m is being pulled up a rough inclined by an agent delevering constant power P. The coefficient of friction between block and incline is $\mu$. The maximum speed of the block during the course of ascent is

asked Aug 6, 2013 by meena.p

1 answer

The potential energy of a force field $\hat F$ is given by $v(x,y)=\cos (x+y)$ . The force acting on the particle at position given by coordinate $(0, \large\frac{\pi}{4})$ is

asked Aug 6, 2013 by meena.p

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A cord is used to lower vertically a block of mass M,a distance d, at a constant downward acceleration $g/4$. Then work done by cord on block

asked Aug 6, 2013 by meena.p

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A $1.0 \;kg$ block collides with a horizontal weightless spring of spring constant $2.0N/m$. The block compresses the spring $4.0\;m$ from the rest position.Assuming that the coefficient of kinetic friction between the block and horizontal surface of $0.25,$ what was the speed of the block at the instant of collision

asked Aug 6, 2013 by meena.p

1 answer

Graph shows the acceleration of a 3 kg particle as an applied force moves it from rest along x-axis. The total work done by the force on the particle by the time the particle reaches $x=6\;m$ is equal to

asked Aug 6, 2013 by meena.p

1 answer

A particle of mass m slides a distance d down a plane inclined at $\theta$ to the horizontal. The work done by the normal reaction R is

asked Aug 6, 2013 by meena.p

1 answer

A car is moving with a constant speed of $20 ms^{-1}$ against a resistive force of $100 \;N$. The power exerted by the car is

asked Aug 6, 2013 by meena.p

1 answer

A 1.5 kg block is initially at rest on a horizontal frictionless surface when a horizontal force in the positive x-axis direction is applied to the block . The force $\hat F$ is given by $\hat F=(4-x^2)\hat i \;N$ . Initial position of the block is $x=0$. The maximum kinetic energy of block between $x=0$ to $x=2.0$ is

asked Aug 6, 2013 by meena.p

1 answer

Two blocks A and B of mass m and 2m are connected by a massless spring of force constant k. They are placed on smooth horizontal plane . Spring is streched by an amount x and then released . the relative velocity of the blocks when the spring come its natural length is

asked Aug 6, 2013 by meena.p

1 answer

Velocity - time graph of a particle moving in a straight line is shown. Mass of particle is 2 kg. What is work done by all the forces on the particle in time interval between $t=0$ to $t=10s$ if velocity goes from $10 ms^{-1}$ to $-20 ms^{-1}$ ?

asked Aug 6, 2013 by meena.p

1 answer

An object of mass m is allowed to fall from rest along a rough inclined plane. The speed of the object at bottom of the plane is proportional to

asked Aug 5, 2013 by meena.p

1 answer

A block of $2 kg$ is hanging over a smooth string. The other end of the string is pulled by a constant force $F=40N$.The kinetic energy of the particle increases $40 \;J$ in a given interval of time. then $(g=10 m/s^2)$

asked Aug 5, 2013 by meena.p

1 answer

A particle moves in a straight line with constant acceleration under constant force F. Select the correct alternatives.

asked Aug 5, 2013 by meena.p

1 answer

System shown in figure is released from rest. Pulley and spring is massless and friction is absent everywhere. The speed of 5kg block when 2 kg block leaves the contact with the ground is $(k=40 N/m;g=10 m/s^2)$

asked Aug 5, 2013 by meena.p

1 answer

A hole is drilled from the surface of earth to its center. A particle is dropped from rest at the surface of earth . The speed of the particle when it reaches the center of the earth in terms of escape velocity of the surface of earth $v_e$ is

asked Aug 5, 2013 by meena.p

1 answer

A particle is released from top of two inclined rough surfaces of height 'h' each. The angle of inclination of two planes are $30^{\circ}$ and $60^{\circ}$ respectively. All other factor (eg. coefficient of friction, mass of block etc) are same in both cases. Let $k_1$ and $k_2$ be kinetic energies of the particle at the bottom of the plane in two cases. Then

asked Aug 5, 2013 by meena.p

1 answer

A particle of mass 2 kg moves on a horizontal plane under the action of force $F=(2 \hat i+2 \hat j)N$. The body is displaced from (0,0) to (1m,1m) If the initial speed of the particle is 2m/s find its final speed

asked Jul 22, 2013 by meena.p

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Potential energy of certain spring when stretched through a distance of $x=10 J$. The amount of work that must be done on this spring to stretch it through an additional distance $x$ will be

asked Jul 22, 2013 by meena.p

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An engine develops 10 KW of power How much time will it take to lift mass of 200 kg to a height of 40 m

asked Jul 22, 2013 by meena.p

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A body of mass m at rest explodes into 3 partrs, having masses in ratio 1:1:3. If two parts having equal masses move at right angles to each other with 10 m/s each , the velocity of third will be

asked Jul 22, 2013 by meena.p

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Water is pumped through a hose-pipe at the rate of 75 lit/min in and issue from a nozzle of cross sectional area of 0.00625 sq-m. The force of reaction of nozzle is

asked Jul 22, 2013 by meena.p

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When kinetic energy of body is increased by 300 % momentum of body is increased by

asked Jul 22, 2013 by meena.p

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A shell is fired from a canon with a velocity v at an angle $\theta$ with the horizontal. At the highest point of its path it explodes into two pieces of equal masses, one of the pieces retraces its path to point of throw. what is speed of second piece immediately after explosion

asked Jul 22, 2013 by meena.p

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When a body is thrown vertically upwards with a velocity 50 m/s, the percentage of its initial kinetic energy converted to potential energy after 4s is $(g=10\;m/s^2)$

asked Jul 22, 2013 by meena.p

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