# Space

 what is weight force? the force on an object due to its position in a gravitational field what is work? the change in energy that occurs when a force is moving an object What is Gravitational Potential energy? (GPE) the work done to move an object from infinity to a point within the gravitational field what is a tajectory and what are it's components? the path a projectile takes as it is moving through the air verticle component is acceleration due to gravityHorizontal component is constant velocity What is escape velocity? the initial velocity required by a projectile to rise vertically and just escape the gravitational field of a planet what is g-force? the measure of acceleration on an object using acceleration due to gravity as a base unit where on the earth and in which direction should a rocket be fired for maximum velocity? on the equator and to the east key features of a low earth orbit 200-1000km above earthfast velocityused for mapping Key features of geostationary orbit 36000kmperiod of 24 hoursused for em communications what causes orbital decay? collision with air particles causing heat what are three issues associated with re-entry of a craft? angle 5-7degreesnose angled upwardsheat ionises surrounding air blocking communications what are the contributions of goddard? helped pioneer first liquid fuel rocketsproved space travel was possible by proving thrust in a vacuumsolved many technical problems what are the five proprties of the aether? fills all spacetransparentpermeates all matterextremely low densityhigh elasticity outline the principle of relativity all motion is relativecant detect v unless you have another frame of reference to compare it to what are the two main ideas of einsteins theory of special relativity? The laws of physics are true in all inertial frames of referencec is constnat explain the relativity of simultaneity events that are simultaneous in one frame of reference when approching c are not for another frame of reference explain mass dilation the mass of an object increases as its speed increases as mass and energy are interconvertible. at speeds approaching C mass increase is exponential explain length contraction the length of an object is affected by its speed relative to others. if a spaceship at C zooms past observed from earth it would seem shorter and earth will seem smaller from the ship explain time dilation time measured by observers that are in relative motion to eachother are different. man in a ship approachin C will see an earth clock moving slower and vice versa what experiment proved einsteins theories? the atomic clocks what are the standards for one second and one metre considering light is the only constant? 1m = the distance light travells in a fraction of a second1s = the time it takes for a specific number of oscillations of the caesium 133 atom what are two problems with travelling at speed of light? at current speeds it would take millions of yearsinfinate mass thus infinate accelerationamount of fuel alone is prohibitive AuthorAnonymous ID108387 Card SetSpace Descriptionspace Updated2011-10-12T13:56:53Z Show Answers