Recent questions tagged cbsc

Newton's first law states

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What does the horizontal line in a distance-time graph represent?

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A car travels 100 m in 5 minutes. What is its average speed?

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Velocity of sound is independent of

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The velocity of sound in dry air is

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On driving a scooter for a long time, the air pressure in the tyres slightly increases

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Cloudy nights are warmer than clear ones because

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

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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.

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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

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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

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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

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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

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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

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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?

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

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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

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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.

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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

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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?

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Submarines are built in accordance with

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If the speed of an object doubles then its kinetic energy

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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?

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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?

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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

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The kinetic energy of a substance is due to the _______ of the atoms contained in it.

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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?

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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

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