Questions by varun

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A satellite orbits the earth at a height of 400 km above the surface. How much energy must be expended to rocket the satellite out of the earth’s gravitational influence? Mass of the satellite = 200 kg; mass of the earth = 6.0×1024 kg; radius of the earth = `6.4 × 10^6` m; G = `6.67 × 10^(–11)` N `m^2`

asked Mar 19, 2022 in 11th Physics

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Two stars each of one solar mass (= `2×10^(30)` kg) are approaching each other for a head on collision. When they are a distance 109 km, their speeds are negligible. What is the speed with which they collide ? The radius of each star is `10^4` km. Assume the stars to remain undistorted until they collide. (Use the known value of

asked Mar 19, 2022 in 11th Physics

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Two heavy spheres each of mass 100 kg and radius 0.10 m are placed 1.0 m apart on a horizontal table. What is the gravitational force and potential at the mid point of the line joining the centres of the spheres ? Is an object placed at that point in equilibrium? If so, is the equilibrium stable or unstable

asked Mar 19, 2022 in 11th Physics

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As you have learnt in the text, a geostationary satellite orbits the earth at a height of nearly 36,000 km from the surface of the earth. What is the potential due to earth’s gravity at the site of this satellite ? (Take the potential energy at infinity to be zero). Mass of the earth = `6.0×10^(24)` kg, radius = 6400

asked Mar 19, 2022 in 11th Physics

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A star 2.5 times the mass of the sun and collapsed to a size of 12 km rotates with a speed of 1.2 rev. per second. (Extremely compact stars of this kind are known as neutron stars. Certain stellar objects called pulsars belong to this category). Will an object placed on its equator remain stuck to its surface due to gravity ? (mass of the sun = `2×10^(30)`

asked Mar 19, 2022 in 11th Physics

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A spaceship is stationed on Mars. How much energy must be expended on the spaceship to launch it out of the solar system ? Mass of the space ship = 1000 kg; mass of the sun = `2×10^(30)` kg; mass of mars = `6.4×10^(23)` kg; radius of mars = 3395 km; radius of the orbit of mars = `2.28 ×10^8` km; G = `6.67 × 10^(–11)` N `m^2`

asked Mar 19, 2022 in 11th Physics

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A rocket is fired ‘vertically’ from the surface of mars with a speed of 2 km s–1. If 20% of its initial energy is lost due to martian atmospheric resistance, how far will the rocket go from the surface of mars before returning to it ? Mass of mars = `6.4×10^(23)` kg; radius of mars = 3395 km; G = G = `6.67 × 10^(–11)` N `m^2`

asked Mar 19, 2022 in 11th Physics

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What is the moment of inertia of a disc about one of its

asked Mar 19, 2022 in 11th Physics

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What is the moment of inertia of a rod of mass M, length l about an axis perpendicular to it through one

asked Mar 19, 2022 in 11th Physics

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What is the moment of inertia of a ring about a tangent to the circle of the

asked Mar 19, 2022 in 11th Physics

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Find the centre of mass of three particles at the vertices of an equilateral triangle. The masses of the particles are 100g, 150g, and 200g respectively. Each side of the equilateral triangle is 0.5m

asked Mar 19, 2022 in 11th Physics

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Find the centre of mass of a triangular

asked Mar 19, 2022 in 11th Physics

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Find the centre of mass of a uniform L-shaped lamina (a thin flat plate) with dimensions as shown. The mass of the lamina is 3

asked Mar 19, 2022 in 11th Physics

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Find the scalar and vector products of two vectors. `a=(3hati-4hatj+5hat)` and

asked Mar 19, 2022 in 11th Physics

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Find the torque of a force `7hati+3hatj-4hatk` about the origin. The force acts on a particle whose position vector is

asked Mar 19, 2022 in 11th Physics

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Show that the angular momentum about any point of a single particle moving with constant velocity remains constant throughout the

asked Mar 19, 2022 in 11th Physics

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Show that moment of a couple does not depend on the point about which you take the

asked Mar 19, 2022 in 11th Physics

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A metal bar 70 cm long and 4.00 kg in mass supported on two knife-edges placed 10 cm from each end. A 6.00 kg load is suspended at 30 cm from one end. Find the reactions at the knifeedges.(Assume the bar to be of uniform cross section and

asked Mar 19, 2022 in 11th Physics

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A 3m long ladder weighing 20 kg leans on a frictionless wall. Its feet rest on the floor 1 m from the wall as shown in Fig.. Find the reaction forces of the wall and the floor.

asked Mar 19, 2022 in 11th Physics

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The angular speed of a motor wheel is increased from 1200 rpm to 3120 rpm in 16 seconds. (i) What is its angular acceleration, assuming the acceleration to be uniform? (ii) How many revolutions does the engine make during this

asked Mar 19, 2022 in 11th Physics

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