Space debris left from old satellites and their launchers is becoming a hazard to other satellites. (a) Calculate the speed of a satellite in an orbit 900 km above Earth’s surface. (b) Suppose a loose rivet is in an orbit of the same radius that intersects the satellite’s orbit at an angle of 90° . What is the velocity of the rivet relative to the satellite just before striking it? (c) If its mass is 0.500 g, and it comes to rest inside the satellite, how much energy in joules is generated by the collision? (Assume the satellite’s velocity does not change appreciably, because its mass is much greater than the rivet’s.)

Assume that we have a distant Star-Planet system with no other planets and the Star is the same as the Sun and the planet is the same as the Earth. This is called an "Earth analog system or "Earth twin". The masses and the orbits are the same except you can assume a perfectly circular orbit.  A) Calculate the equation for the orbital velocity of a planet on a circular orbit. To do this use the equation for average speed: distance=rate x time. In a circular orbit, the speed is always the same, so you can use a time that is one full orbital period (1 year). What is the distance that a planet on a circular orbit travels in this time? Calculate the speed of the Earth twin in meters/second.  Mass of the sun: 2 x 1030 kg. Mass of the Earth: 5.97 x 1024kg (Note: I think I understand how to use the distance= rate x time, but I'm not sure what to input for rate in this situation. I am also not sure how to calculate the speed of the Earth twin)

The radius of Mars is about 3376 km, and its mass about 0.1 times that of the earth. What will be the velocity of a satellite circling Mars at a distance of 10 000 km from the centre of the planet?

The acceleration of gravity is 9 m/s² at the surface of a planet of radius R=10°m. A satellite is to be launched from this planet into a circular orbit of radius 4R. (Probs. 8&9) 8. Find a value for the speed of this satellite when it is in this orbit. 9. Find the value of the initial velocity vo at which this satellite must be launched from the surface of the planet so that it reaches this orbit.