Tuesday, 11 September 2012

PROBLEM:1.233

  Find approximately the third cosmic velocity v3, i.e. the minimum velocity that has to be imparted to a body relative to the Earth’s surface to drive it out of the Solar system. The rotation of the Earth about its own axis is to be neglected.


PROBLEM:1.232

 What is the minimum work that has to be performed to bring a spaceship of mass m = 2.0*103 kg from the surface of the Earth to the Moon?


PROBLEM:1.231

 At what distance from the centre of the Moon is the point at which the strength of the resultant of the Earth’s and Moon’s gravitational fields is equal to zero? The Earth’s mass is assumed to be n = 81 times that of the Moon, and the distance between the cen­tres of these planets 60 times greater than the radius of the Earth R.


PROBLEM:1.230

 A spaceship is launched into a circular orbit close to the Earth’s surface. What additional velocity has to be imparted to the spaceship to overcome the gravitational pull?


PROBLEM:1.229

  A spaceship approaches the Moon along a parabolic trajec­tory which is almost tangent to the Moon’s surface. At the moment of the maximum approach the  brake rocket was fired for a short time interval, and the spaceship was transferred into a circular orbit of a Moon satellite. Find how the spaceship velocity modulus increased in the process of braking.


PROBLEM:1.228

Calculate the orbital and escape velocities for the Moon. Compare the results obtained with the corresponding velocities for the Earth.


PROBLEM:1.227

An artificial satellite of the Moon revolves in a circular orbit whose radius exceeds the radius of the Moon r) times. In the process of motion the satellite experiences a slight resistance due to cosmic dust. Assuming the resistance force to depend on the velocity of the satellite as F = av2, where a is a constant, find how long the satellite will stay in orbit until it falls onto the Moon’s surface.


PROBLEM:1.226

  A satellite must move in the equatorial plane of the Earth close to its surface either in the Earth’s rotation direction or against it. Find how many times the kinetic energy of the satellite in the latter case exceeds that in the former case (in the reference frame fixed to the Earth).


PROBLEM:1.225

 A satellite revolves from east to west in a circular equatorial orbit of radius R = 1.00*104 km around the Earth. Find the velocity and the acceleration of the satellite in the reference frame fixed to the Earth.


PROBLEM:1.224

A satellite revolving in a circular equatorial orbit of ra­dius R = 2.00*104 km from west to east appears over a certain point at the equator every t=11.6 hours. Using these data, calculate the mass of the Earth. The gravitational constant is supposed to be known.


PROBLEM:1.223

   Calculate the radius of the circular orbit of a stationary Earth’s satellite, which remains motionless with respect to its sur­face. What are its velocity and acceleration in the inertial reference frame fixed at a given moment to the centre of the Earth?


PROBLEM:1.222

 An artificial satellite is launched into a circular orbit around the Earth with velocity v relative to the reference frame moving transitionally and fixed to the Earth’s rotation axis. Find the distance from the satellite to the Earth’s surface. The radius of the Earth and the free-fall acceleration on its surface are supposed to be known.

PROBLEM:1.221

On the pole of the Earth a body is imparted velocity v0 directed vertically up. Knowing the radius of the Earth and the free- fall acceleration on its surface, find the height to which the body will ascend. The air drag is to be neglected.


PROBLEM:1.220

 At what height over the Earth’s pole the free-fall accele­ration decreases by one per cent; by half?


PROBLEM:1.219

 Calculate the ratios of the following accelerations: the acceleration w1 due to the gravitational force on the Earth’s surface the acceleration w2 due to the centrifugal force of inertia on the Earth’s equator, and the acceleration w3 caused by the Sun to the bodies on the Earth.


PROBLEM:1.218

Two Earth’s satellites move in a common plane along cir­cular orbits. The orbital radius of one satellite r = 7000 km while that of the other satellite is 70 km less. What time interval separates the periodic approaches of the satellites to each other over the minimum distance?



PROBLEM:1.217


  Find the proper potential energy of gravitational interac­tion of matter forming
(a)   a thin uniform spherical layer of mass m and radius R;
(b) a uniform sphere of mass m and radius R (make use of the answer to Problem 1.214).



PROBLEM:1.216

   A uniform sphere has a mass M and radius R. Find the pressure p inside the sphere, caused by gravitational compression, as a function of the distance r from its centre. Evaluate p at the centre of the Earth, assuming it to be a uniform sphere.


PROBLEM:1.215

 Inside a uniform sphere of density p there is a spherical cavity whose centre is at a distance I from the centre of the sphere. Find the strength G of the gravitational field inside the cavity.


PROBLEM:1.214


There is a uniform sphere of mass M and radius R. Find the strength G and the potential of the gravitational field of this sphere as a function of the distance r from its centre (with r is less than R and grater than R). Draw the approximate plots of the functions G (r) and V(r).


PROBLEM:1.213

 A particle of mass m was transferred from the centre of the base of a uniform hemisphere of mass M and radius R into infinity.What work was performed in the process by the gravitational force exerted on the particle by the hemisphere?


PROBLEM:1.212

Demonstrate that the gravitational force acting on a par­ticle A inside a uniform spherical layer of matter is equal to zero.


PROBLEM:1.211

     A particle of mass m is located outside a uniform sphere of mass M at a distance r from its centre. Find:`
(a)     the potential energy of gravitational interaction of the particle and the sphere;
(b)   the gravitational force which the sphere exerts on the particle.


PROBLEM:1.210

  A cosmic body A moves to the Sun with velocity v0 (when far from the Sun) and aiming parameter L the arm of the vector v0 relative to the centre of the Sun .


 Find the minimum dis­tance by which this body will get to the Sun.


PROBLEM:1.209


A planet A moves along an elliptical orbit around the Sun. At the moment when it was at the distance r0 from the Sun its velo­city was equal to v0 and the angle between the radius vector r0 and the velocity vector v0 was equal to a. Find the maximum and mini­mum distances that will separate this planet from the Sun during its orbital motion.


PROBLEM:1.208


Using the conservation laws, demonstrate that the total mechanical energy of a planet of mass m moving around the Sun along an ellipse depends only on its semi-major axis a. Find this energy as a function of a


PROBLEM:1.207

A planet of mass m moves along an ellipse around the Sun so that its maximum and minimum distances from the Sun are equal to rand r2 respectively. Find the angular momentum M of this planet relative to the centre of the Sun.


PROBLEM:1.206

   Find the potential energy of the gravitational interaction
(a)   of two mass points of masses m1 and m2 located at a distance r from each other;
(b)   of a mass point of mass m and a thin uniform rod of mass M and length L, if they are located along a straight line at a distance a from each other; also find the force of their interaction.