2013 HSC COURSE

1. When object is no longer in a gravitational field

1. at infinity (0J)

1. At the surface of the object providing the gravitational field

1. parabolic path due to gravity
2. path seperated into horizontal and vertical componants 
3. ∆x spans equal distances over equal time periods. Therefore Ux = Vx and ∆x = Uxt
4. ∆y spans differing distances over equal time periods due to the effect of gravity. Therefore   Vy² = Uy² + 2a∆y and ∆y = Uyt + 1/2 at²
5. Ux = Ucosα Uy = Usinα also works for R and V

1. Galileo predicted all objects regardless of mass fell at the same rate. i.e. a is constant for all objects (ignoring air resistance)

1. Aim: to predict the range of a projectile given initial height and Vx. 2. Risk: balls on the ground pose a significant safety hazard as people may slip on them and injure themselves. Therefore pick up any balls on the ground immeadiatly. 3. Materials: 1x wooden ramp 1x retord stand 1x boss head and clamp 1x table 1x metal ball 1x cup 1x stopwatch 4 Method: 1.set up apparatus 2. measure sH, the distance from the edge of the ramp to the edge of the table. 2. release the ball from a marked position on the ramp 4. measure the time take for the ball to cover the distance sH 5. repeat 5x and calculate average time take. 6. calculate the Vavg over sH. Vavg = V at edge of the table = Vx 7. measure ∆y and calculate the theoretical time for the ball to reach the floor from the edge of the table. (∆y = Uyt +1/2 at^2 and Uy = 0) 8. using the value for Ux and t predict ∆x (∆x = Uxt) 9. move the ramp foward by a distance sH/2 place cup at predicted ∆x and test theory (sH/2 compensates for decelleration across the desk) 5. results: the ball landed very close to the predicted ∆x (approximately 1/2cm out) 6. discussion: the repetition of results ensured reliablility. measurements were accurate to a 1/2 mm. Experimental error, as the ball came off the ramp it bounced. 7. Conclusion: The range of the projectile motion of the metal ball was estimated accurately using initial hight and Vx. The slight offshot occured as a result of a flaw in the design of the experiment.

1.Vescape is the initial velocity required by an object to rise vertically and just escape the gravitational field of an object i.e. travel to infinity. 2.This is assuming there is no friction with the atmosphere 3. Ek --> Ep 4. Vesc = root(2Gmp/rp) 5. This hypothetical, in rocket launches etc... the heat produced and g forces would be to great.

newton's concept of escape velocity is a thought experiment in which newton invisaged firing a cannon ball horizontally from a very powerful cannon on top of a very high mountain. At lower velocities the trajectories would be parabolic under the influence of gravity. As the velocity at which the cannon ball was fired increased so to would the range of the cannonball. When the velocity was such that (mv^2)/r = (Gm1m2)/r i.e v = root(Gm/r) the cannonball would orbit the earth - as it fell towards the earth under the influence of gravity the earth would curve away from it

1. used to express apparent weight as a proportion of true weight 2. G-force = R/W where R = reaction force (external force acting/apparent weight) and W = true weight (mg on earth) 3. G-force = (+ - a+g)/g

1. One of the first outside Russia to suggest the possibility of space travel. 2, 1914 patented designs for a liquid fuelled rocket. Liquid fuel more efficient than black fuels, lighter which results in greater acceleration of the rocket as the mass decreases and the rate of burn may be throttled, stopped or restarted. used in all modern day rocketry since sputnik 3. 1914 patented designs for a multistaged rocket. In multistaged rockets as the rocket stage empties it may be jettisoned away from the craft thereby increasing the crafts acceleration by decreasing the crafts weight. e.g atlata 1 and atlas 2 launch vehicles 4. Descovered the optimum rocked nozzle design. De lavel nozzle (from steam turbine) converts low velocity high pressure into low pressure high velocity.eg in the space shuttle apollo missions

1. the earth rotates on its axis from W to E over a period of 24 hours. 2. v = (2πr)/t therefore at the equator where the earth's radius is larges (r = 6.38x10^6) The rotational velocity = 464ms^-1 W to E.

1. The earth orbits around the sun over a period of 24 hours in which r = 1.5 x 10^11 m. 2. v = (2πr)/t = 30000 ms^-1

1. Since all motion is relative. Space craft launched may utilised the rotation and orbital motion in order to increase their relative velocities to the sun without having to use any fuel. 2. This means not only is there a velocity boost in space flights but also less fuel is needed.3. The decrease in fuel means that the craft will have a smaller mass and therefore a greater acceleration (F=ma) and will also decrease costs.

During launch there are two forces; Thrust (T) and W(weight). By Newton's Law ΣF = ma. Therefore a = ΣF/m = (T - mg)/m. As the mass of the rocket decreases throughout the flight (as fuel is burnt) and T remains constant the acceleration and ΣF of the of the rocket and the astronaut increases throughout flight.

single word or short phrase, usually interrupting normal syntax, used to lend emphasis to the words immediately proximate to the adverb e.g. "in fact"

omitting conjunctions between words, phrases, or clauses. In a list of items, asyndeton gives the effect of unpremeditated multiplicity, of an extemporaneous rather than a labored account:

use of a conjunction between each word, phrase, or clause. The rhetorical effect of polysyndeton is a feeling of multiplicity, energetic enumeration, and building up.

deliberately expresses an idea as less important than it actually is, either for ironic emphasis or for politeness and tact

recurrent syntactical similarity. Several parts of a sentence or several sentences are expressed similarly to show that the ideas in the parts or sentences are equal in importance. Parallelism also adds balance and rhythm and, most importantly, clarity to the sentence.

the second part of a grammatical construction is balanced or paralleled by the first part, only in reverse order in order to add balance, rhythm and clarity.

establishes a clear, contrasting relationship between two ideas by joining them together or juxtaposing them, often in parallel structure.

the repetition of the same word or words at the beginning of successive phrases, clauses, or sentences, commonly in conjunction with climax and with parallelism:

repetition of the same word or words comes at the end of successive phrases, clauses, or sentences:

repeats the last word of one phrase, clause, or sentence at or very near the beginning of the next. it can be generated in series for the sake of beauty or to give a sense of logical progression

repeats the beginning word of a clause or sentence at the end

consists of raising one or more questions and then proceeding to answer them, usually at some length

raising one or more questions thats are not answered by the writer, because its answer is obvious or obviously desired, and usually just a yes or no. It is used for effect, emphasis, or provocation, or for drawing a conclusionary statement from the facts at hand.

consists of a brief statement of what has been said and what will follow. It might be called a linking, running, or transitional summary, whose function is to keep the discussion ordered and clear in its progress:

an explicit reference to a particular meaning or to the various meanings of a word, in order to remove or prevent ambiguity.

involves repeating a word or expression while adding more detail to it, in order to emphasize what might otherwise be passed over. In other words, amplification allows you to call attention to, emphasize, and expand a word or idea to make sure the reader realizes its importance or centrality in the discussion.

emphasizes an idea by expressing it in a string of generally synonymous phrases or statements.

asserts or emphasizes something by pointedly seeming to pass over, ignore, or deny it.

qualifies a statement by recalling it (or part of it) and expressing it in a better, milder, or stronger way. A negative is often used to do the recalling:

extravagant, implied metaphor using words in an alien or unusual way