1. Light travels at a speed of 3x10^8 metres per second. How long will it take light to travel a distance of 9x10^23 metres? Give answer in standard form.

2. the mass of a neuron is 5.84x10^-24 grams. Calculate the total mass of 4.3 x10^6. give answer in standard form correct to 3 significant figures.

3. the distance from earth to the star proxima centauri is 4.22 light years. 1 light year = 9.461 x 10^12 km. work out the distance in kilometres from earth to the star proxima centauri. Give answer in standard form for correct to 3 significant figures.

4. explain when a situation will lead to a linear graph and when to a non-linear graph.

5. explain the usefulness of graphs in displaying the results of scientific experiments. State some examples.

6. justify the level of accuracy in the use of particular types of data collection methods in laboratory experiments.

1. light travels at a speed of 3x10^8 metres per second. How long will it take light to travel a distance of 9x10^23 metres? Give answer in standard form.


Distance = rate \times time

Your distance is 9 \times 10^{23}\,meters

Your rate is 3 \times 10^8\,\frac {meters}{sec}

meters \div \frac {meters}{sec} = sec or meters \, \times \, \frac {seconds}{meter} = sec

You can do the arithmetic.



2. the mass of a neuron is 5.84x10^-24 grams. Calculate the total mass of 4.3 x10^6. give answer in standard form correct to 3 significant figures.


Just divide mass \div \frac {mass}{neutron} = number of neutrons



3. the distance from earth to the star proxima centauri is 4.22 light years. 1 light year = 9.461 x 10^12 km. work out the distance in kilometres from earth to the star proxima centauri. Give answer in standard form for correct to 3 significant figures.


(light\,years)\times \frac {meters}{light\,year}=meters



4. explain when a situation will lead to a linear graph and when to a non-linear graph.


If a situation can be described by a linear equation (an equation of the form y=mx+b), use a linear graph.



5. explain the usefulness of graphs in displaying the results of scientific experiments. State some examples.


Graphs summarize a lot of data in a small, conveniently understood (if done right) space.



6. justify the level of accuracy in the use of particular types of data collection methods in laboratory experiments.


I think you must have talked about this in school. If you measure something to a particular level of accuracy, there is always an error in that measurement. For example, let's say I have a balance that weighs accurately to within one gram. The balance says that something weighs 10 grams. That means the object must weigh between 9.5 grams and 10.5 grams. We don't really know what (unless we weigh it on a more accurate balance). If you report the weight as 9.89412341, the ".89412341" is really way beyond what is reasonable for the measurement.

Distance = rate \times time

Your distance is 9 \times 10^{23}\,meters

Your rate is 3 \times 10^8\,\frac {meters}{sec}

meters \div \frac {meters}{sec} = sec or meters \, \times \, \frac {seconds}{meter} = sec

You can do the arithmetic.



Just divide mass \div \frac {mass}{neutron} = number of neutrons



(light\,years)\times \frac {meters}{light\,year}=meters



If a situation can be described by a linear equation (an equation of the form y=mx+b), use a linear graph.



Graphs summarize a lot of data in a small, conveniently understood (if done right) space.



I think you must have talked about this in school. If you measure something to a particular level of accuracy, there is always an error in that measurement. For example, let's say I have a balance that weighs accurately to within one gram. The balance says that something weighs 10 grams. That means the object must weigh between 9.5 grams and 10.5 grams. We don't really know what (unless we weigh it on a more accurate balance). If you report the weight as 9.89412341, the ".89412341" is really way beyond what is reasonable for the measurement.

thank you for this it helpedme but i still do not understand 1, 2 and 3. please can you show me where to put the numbers in so i am able to wrk it out. Thank you

Sorry. We won't do your homework for you. You would learn nothing that way and I don't want that on my conscience. This is nearly trivial. I gave you the formulas -- in many cases I gave you much more than I should have. You do the arithmetic.