Recent questions tagged work-power-energy

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

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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

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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

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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

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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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Due to the application of a force body of mass 1.5 kg is moving up vertically with an acceleration of $1.2 m/s^2$ for $10 \;s$, starting from rest, What is power of the agent doing work?

asked Jul 22, 2013 by meena.p

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A bucket of water weighing 20 kg is slowly raised from depth of 20 m to ground level by a roap. The mass of rope is 1.2 kg per meter. Find the work done

asked Jul 22, 2013 by meena.p

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An engine of weight 6.5 metric ton is going up an incline of $\large\frac{5}{13}$ at the rate of $9\; km/hr$ .The power of engine , if co-efficient of friction is $\large\frac{1}{12}$ is

asked Jul 22, 2013 by meena.p

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A man throws the brick to a height of 12 m with a speed of 12 m/s. If he throws the brick in such a way that they just reach that height , what percentage of energy will be saved

asked Jul 20, 2013 by meena.p

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Ice cube of size $100\;cm$ and area of base $(500 m \times 50 m)$ is floating in a tank partially filled with water. The change in gravitational potential energy, when ice melts completely (density of Ice is $900\;kg/m^3$)

asked Jul 19, 2013 by meena.p

1 answer

Power supplied to a particle of mass 2 kg varies with time is $P=\large\frac{3t^2}{2}$ watt, velocity of particle at $t=0$ is $v=0.$ The velocity of particle at $t=2s$ will be

asked Jul 19, 2013 by meena.p

1 answer

A particle of mass m is projected with velocity u at an angle $\alpha$ with horizontal. During the period when particle decends from highest point to the position where its velocity vector makes $\alpha/2$ angle with horizontal, work done by gravity force is

asked Jul 19, 2013 by meena.p

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A particle is given an initial speed u inside a smooth spherical shell of radius $R=1m$ that it is just able to complete the circle. Acceleration of the particle when its velocity is vertical is

asked Jul 19, 2013 by meena.p

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A bullet fired from rifle. The ratio of kinetic energy of rifle to that of bullet after firing is

asked Jul 19, 2013 by meena.p

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A Block of mass 'm' are kept on a smooth horizontal plane, and attached to two unstretched spring with spring constants $k_1$ and $k_2$ as shown. If the block be displaced by a distance x on either side and released then the velocity of block as it passes through the mean position is

asked Jul 19, 2013 by meena.p

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A car of mass m moving at a speed v is stopped in distance x by friction between tyres and road. If kinetic energy of the car is doubled. its stopping distance will be

asked Jul 19, 2013 by meena.p

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Ball 1 collides with an another identical ball 2 at rest For what values of coefficient of restitution e the velocity of 2nd ball becomes two times of ball 1 after collision?

asked Jul 19, 2013 by meena.p

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Hail storms are observed to strike the surface of frozen lake at $30^{\circ }$ with the vertical and rebound at $60^{\circ}$ with vertical, Assume contact to be smooth, the coefficient of restitution,

asked Jul 19, 2013 by meena.p

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A fire hose has a diameter of 2.5 cm and is required to direct jet of water to height of at least 40 m. The minimum power of pump needed is

asked Jul 18, 2013 by meena.p

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Two blocks are resting on a floor as shown. There is no friction between floor and lower block (M=3 kg) but frictional coefficient between both blocks is 0.2. Both blocks move together with initial speed V towards the spring ,compresses it and due to force exerted by spring moves in reverse direction of initial motion. What is maximum value of V in (m/s), so that during motion there is no slipping between the blocks.

asked Jul 18, 2013 by meena.p

1 answer

A heavy particle hanging from fixed point by light inextensible string of length l is projected horizontally with speed $\sqrt {gl}$. Find speed of particle at the instant of the motion when tension in the string is equal to weight of particle

asked Jul 18, 2013 by meena.p

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In the arrangement shown mass m is released from rest with the spring unstretched . The force constant of spring is K. The maximum extension in the spring

asked Jul 18, 2013 by meena.p

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A pigeon in flight experiences a force of air resistance given by $F=bv^2$, where v is the flight speed and b is constant. What is maximum speed of pigeon if its power output is P

asked Jul 18, 2013 by meena.p

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In the figure shown, a particle is released from the position A on a smooth track. When particle reaches B, the normal reaction on it by the track is

asked Jul 18, 2013 by meena.p

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From an automatic gun a man fires 360 bullets per minute with speed of 360 km/hr. If each weighs 20g the power of gun

asked Jul 18, 2013 by meena.p

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A block of mass $m$ initially at rest is dropped from a height $ h$ on to a spring of force constant $k$. The maximum compression in spring is $x$ ,then

asked Jul 18, 2013 by meena.p

1 answer

A car of mass m is driven with acceleration 'a' along a straight level road against a constant external resistive force 'R'. when velocity of car is 'V', the rate at which the engine of car is doing work will be

asked Jul 18, 2013 by meena.p

1 answer

A ball is released from certain height.It loses 50 % of its kinetic energy on striking ground. It will attain height again equal to

asked Jul 18, 2013 by meena.p

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A body of mass 10 kg at rest is acted upon simultaneously by two forces 4N and 3N at right angles to each other. The kinetic energy of body at end of 10sec is

asked Jul 18, 2013 by meena.p

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If the unit of force and length each increased by 4 times , then the unit of energy is increased by

asked Jul 18, 2013 by meena.p

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Calculate work done to move a body of mass 10 kg along an incline $(\theta=30^{\circ})$ with constant velocity through a distance 10 m $(g=10 m/s^2)$

asked Jul 18, 2013 by meena.p

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A ball is moving with velocity 3m/s towards a heavy wall which is moving towards the ball with speed 1m/s. Assuming collision to be elastic, find the velocity of ball immediately after collision

asked Jul 17, 2013 by meena.p

1 answer

A sphere of mass m moving with velocity v enters, a hanging bag of sand and stops. If the mass of bag is M and it is raised by height h, then the velocity of sphere was

asked Jul 17, 2013 by meena.p

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A chain of mass M is placed on a smooth table with $\large\frac{1}{n}$$^{th}$ of its length L hanging over the edge. The work done in pulling the hanging portion of chain back to the surface of table is

asked Jul 17, 2013 by meena.p

1 answer

An object of mass 1 kg travelling at 5.0 m/s enters a region of ice where the coefficient of kinetic friction is .10. Find the distance the object travels before coming to rest.

asked Jul 17, 2013 by meena.p

1 answer

A ball is dropped from a height of h from ground. If the coefficient of restitution is e, the height to which the ball goes up after it rebounds for the nth time is

asked Jul 17, 2013 by meena.p

2 answers

A spring with a spring force constant $k=800\; N/m$ has a length of 5 cm. The work done in extending from 5 cm to 15 cm is

asked Jul 17, 2013 by meena.p

1 answer

A 50kg man with 20kg load on his head climbs up 20 steps of 0.25m height each. The work done in climbing is

asked Jul 17, 2013 by meena.p

1 answer

There will be an increase in potential energy of the system if work is done upon the system by

asked Jul 17, 2013 by meena.p

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A block of weight $W$ is pulled along a distance $d$ on a table. The work done by the weight is

asked Jul 17, 2013 by meena.p

1 answer

A block of mass 5 kg is being raised vertically upward by the help of a string attached to it. It rises with an acceleration of $2m/s^2$. The block rises by 2.5 m .the work done by tension and work done against gravity are respectively

asked Jul 17, 2013 by meena.p

1 answer

A force of 0.5 N acts on body of mass 5 kg initially at rest for one minute. Find the work done by the force.

asked Jul 17, 2013 by meena.p

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