Recent questions tagged class 9

When a body is immersed partially or fully in a fluid, the _______ force from the surrounding fluid acts on the body.

asked Oct 31, 2017 by priyanka.c

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The bags and suitcases are provided with broad handles

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In any kind of collision

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When a body is thrown up, work done by gravity is

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Work done is a

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Which of the following statement is not true? 1. The velocity in uniform motion doe not depend upon the time interval 2. External force is required for an object to be in uniform motion 3. For a uniform motion along a straight line in a given direction, the magnitude of the displacement is not equal to the actual distance covered by the object. 4. The average speed is equal to the arithmetic mean of individual speeds.

asked Oct 31, 2017 by priyanka.c

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A rocket with a lift off mass 20,000 kg is balanced with a net initial acceleration of 5 $m/s^2$, then the initial thrust of the blast is

asked Oct 31, 2017 by priyanka.c

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Read the following passage and answer the question below A uniform circular motion is the motion of an object travelling at a constant speed along a circular path. Centripetal force is the force required to move the body uniformly in a circle. This force acts along the radius and towards the centre of the circle. In fact when a body moves in a circle, the direction of motion at any instant is along the tangent to the circle at that instant. In other words the direction of motion of a body goes on changing continuously. According to Newton's 1st law of motion, a body cannot change its direction of motion by itself. An external force is required for this purpose. It is this force which is called as the centripetal force. On account of a continuous change in the direction of motion of the body, there is a change in the velocity of the body. Hence it undergoes an acceleration which is called centripetal acceleration. QUESTION : Centripetal force is the force which always acts ________ the centre

asked Oct 31, 2017 by priyanka.c

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Read the passage below and answer the question A uniform circular motion is the motion of an object travelling at a constant speed along a circular path. Centripetal force is the force required to move the body uniformly in a circle. This force acts along the radius and towards the centre of the circle. In fact when a body moves in a circle, the direction of motion at any instant is along the tangent to the circle at that instant. In other words the direction of motion of a body goes on changing continuously. According to Newton's 1st law of motion, a body cannot change its direction of motion by itself. An external force is required for this purpose. It is this force which is called as the centripetal force. On account of a continuous change in the direction of motion of the body, there is a change in the velocity of the body. Hence it undergoes an acceleration which is called centripetal acceleration. QUESTION : Motion of a body along a circle is

asked Oct 31, 2017 by priyanka.c

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The bouncing of a rubber ball on a cement floor is an example of

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When a spring is pulled the work done by the spring force is

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The mechanical energy of a system is

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Whenever there is no loss in kinetic energy during collision it is called

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Read the passage below and answer the question In considering the effect of force on motion, linear momentum is very important. This can be understood from the following examples: 1. We know that a much greater force is required to push a truck than a car to bring them to the same speed in the same time. Similarly a greater opposing force is needed to stop a heavy body than a light body in the same time, when they are moving with the same speed. Thus the mass of a body is an important parameter that determines the effect of force in its motion. 2. Speed is another parameter to consider. A bullet fired from a gun can easily pierce through a target like human tissue, before it stops, resulting in grave injury. The same bullet thrown at a moderate speed can be easily stopped. Thus for a given mass, greater is the speed, greater is the opposing force needed to stop the body in a certain time. QUESTION : When we consider the effect of force on its motion

asked Oct 31, 2017 by priyanka.c

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Read the passage below and answer the question In considering the effect of force on motion, linear momentum is very important. This can be understood from the following examples: 1. We know that a much greater force is required to push a truck than a car to bring them to the same speed in the same time. Similarly a greater opposing force is needed to stop a heavy body than a light body in the same time, when they are moving with the same speed. Thus the mass of a body is an important parameter that determines the effect of force in its motion. 2. Speed is another parameter to consider. A bullet fired from a gun can easily pierce through a target like human tissue, before it stops, resulting in grave injury. The same bullet thrown at a moderate speed can be easily stopped. Thus for a given mass, greater is the speed, greater is the opposing force needed to stop the body in a certain time. QUESTION : The important parameters of linear momentum are

asked Oct 31, 2017 by priyanka.c

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The function of mud guards in a vehicle is due to

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A train of 150 m/s if travelling towards north direction at a speed of 10 m/s. A bird flies at a speed of 5 m/s towards sound direction along the railway track. What will be the time taken by the bird to cross the train?

asked Oct 31, 2017 by priyanka.c

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Under what conditions is the average velocity equal to the instantaneous velocity?

asked Oct 31, 2017 by priyanka.c

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The branch of physics which deals with the study of material objects at rest is called

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What will be the weight of an object at the centre of the earth?

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Why is gravitational potential energy negative?

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When the separation between two bodies is of infinite distance then the gravitational force is

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Which of the following are correct statements. When a wave passes through a medium 1. the particles of the medium are disturbed 2. the energy of the medium is disturbed 3. the velocity of particles through the medium remains a constant 4. there is a change in density and pressure of the particles

asked Oct 31, 2017 by priyanka.c

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The relation between wavelength, velocity and frequency of sound waves is given by

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An object moving with a speed greater than the speed of sound is said to have

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Which of the following increases as wavelength decreases if the velocity remains a constant.

asked Oct 31, 2017 by priyanka.c

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Which of the following statements are true? 1. Frequency of the vibration of a particle is defined as number of vibrations completed by the particle in one second. 2. Wave motion is the sort of disturbance which travels through the medium. 3. Velocity of sound in dry air is grater than the velocity of sound in moist air 4. Seismic waves are examples of mechanical waves

asked Oct 30, 2017 by priyanka.c

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The pitch of a wave depends upon its

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The frequency of a sound wave

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An object of mass 30 kg displaces a liquid that weights 300 N when placed inside the liquid. Will the object float or sink?

asked Oct 30, 2017 by priyanka.c

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Submarines are built in accordance with

asked Oct 30, 2017 by priyanka.c

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If the speed of an object doubles then its kinetic energy

asked Oct 30, 2017 by priyanka.c

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Two people A and B carry some load from the road to the roof of the bus. A takes 1 min and B takes 2 minutes to do the same job. Who has done more work A or B?

asked Oct 30, 2017 by priyanka.c

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A body covers a distance of x meters along a circular path. The ration of the distance to that of displacement is

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What causes the change in mechanical energy to thermal energy?

asked Oct 30, 2017 by priyanka.c

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Newton's third law is also called as

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The total amount of kinetic and potential energy of a system is called

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An object falls off a height of 3m does a work of 147 Joules. Then the mass of the box is

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An object rolling down an inclined plane with a velocity of xm/s, then its acceleration is

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Which of the following does not require direction

asked Oct 30, 2017 by priyanka.c

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Read the following passage and answer the question given below A transvers wave motion is that wave motion in which individual particles of the medium execute simple harmonic motion about their mean position in a direction perpendicular to the direction of propagation of wave motion. A transverse wave travels through the medium in the form of crests and troughs. The distance between two consecutive crests or two consecutive trough is called wavelength of the wave. It is represented by λ. A longitudinal wave motion is that wave motion in which the individual particles of the medium execute simple harmonic motion about their mean position along the same direction, along which the wave is propagated. A longitudinal wave travels in the form of compressions and rarefactions. The distance between two compressions or rarefactions is the wavelength of the wave. QUESTION : Transverse waves cannot be produced in liquids and gases why?

asked Oct 30, 2017 by priyanka.c

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Read the following passage and answer the question given below A transvers wave motion is that wave motion in which individual particles of the medium execute simple harmonic motion about their mean position in a direction perpendicular to the direction of propagation of wave motion. A transverse wave travels through the medium in the form of crests and troughs. The distance between two consecutive crests or two consecutive trough is called wavelength of the wave. It is represented by λ. A longitudinal wave motion is that wave motion in which the individual particles of the medium execute simple harmonic motion about their mean position along the same direction, along which the wave is propagated. A longitudinal wave travels in the form of compressions and rarefactions. The distance between two compressions or rarefactions is the wavelength of the wave. QUESTION : Waves on strings are always

asked Oct 30, 2017 by priyanka.c

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It is painful to walk bare footed on a road converted with pebbles because

asked Oct 30, 2017 by priyanka.c

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Which of the following statements are not correct? 1. The pressure is different at different points inside the liquid lying at the same depth in a horizontal plane 2. Pressure exerted by a liquid is independent of the shape of the containing vessel 3. Density is mass per unit area of the substance 4. Relative density of a substance is defined as the ratio of its density to the density of water

asked Oct 30, 2017 by priyanka.c

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Name the invisible forces of attraction between masses

asked Oct 29, 2017 by priyanka.c

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The net force on an object will be zero if

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The weight of the object

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Of the three laws of motion, which law is the real law of motion?

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Newton's second law describes the relation between _, and __

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For a maximum work to be done, which of the following combination of force and distance will be required?

asked Oct 29, 2017 by priyanka.c

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