8/12/2019 Grade 10 Test

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Instructions1. The test is strictly Physics questions only and it is an OPEN BOOK TEST ( you can use a

textbook or anything that you think can help you answer the questions)2. You need only answer the FIRST 3 compulsory questions only.3. Each question contributes 33.33% to towards your final mark of 99.99%.4. Question 4 is an OPTIONAL BONUSquestion and only the bravecan answer the question.5. If one chooses to answer the bonus question which counts 50.01% and gets the question

correct, the student will have a final mark of 150%.

6. If one chooses to answer the bonus question and gets it incorrectly 20% will be subtractedfrom your test mark!

7. Number your questions according to the numbering system on this test.8. Show all workings CLEARLY and NEATLY if I dont see what you wrote you will get aZERO!!!

Question1

During the Easter holidays I had the opportunity to go to the Rand Easter Show and while I

was there, there was an F-16 Fighting Falcon Multirole Fighter aircraft. This aircraft is

capable of flying at speeds 5 times the speed of sound!!! But unfortunately it costs R5000 to

take a single trip around Johannesburg (. ). So since I had nomoney to take the ride, I decided to do a little bit of physics something even more fun than

riding the aircraft. Supposed the Fighter falcon had a Mach 3 speed (Mach 1 = ).

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Using your knowledge of Mathematics and Physics,

1. How long will it take for the aircraft to move across the whole of Johannesburgarea?

(Assuming that it moves in a straight line)

Hint: first find the diameter of Johannesburg using the appropriate formula given

then use your knowledge of physics to find the time

2. At what frequency was it moving at?3. What do you think the wavelength would be in this case?

(No need for a calculation, you already calculated it)

Useful formulas: = (22

= , =

Question 2

Yesterday while I was watching Animal Planet, they were talking about electric eels. These

are fish found in the waters of South America (SouthAfricans are safe!!!) A large grown

electric eel is capable of generating 500 electric shock through 28 feet of still water. Theshock is strong enough to harm any large animal, including us humans. So yet again I

decided to do some fun stuff with Physics. The skin of the electric eel also serves as a large

biological resistor (made up of small resistors).

Using your knowledge of Physics,

1. Find the total parallel resistance.2. Find the total resistance in the circuit.3. How much current did it generate?4. What is the total power of the 500V electric shock?5. From your findings can an electric eel power up a 2000 Watt bar heater?

(If it does power up the heater, I might consider using electric eels to light up my

house in the near future)

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Question 3

In the mid 1800 Sir Isaac Newton completely described lightand its properties. Then in the

1900s Albert Einstein wrote a master piece of work called Theory of Special Relativity.

Einstein said nothing in the whole universe can move faster than the speed of light (if thiswas not truth the whole of physics principles would be wrong, in a nutshell we would be

seeing Ghosts!!!). Speed of light is absolute

The picture below shows the Electromagnetic spectrum and all electromagnetic waves

move at a speed of light ( = 3 1 08 )

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1, List all electromagnetic waves and for each give at least 5 examples where it is used or

found. (The more you give the more marks I will give you)

2, Explain in not less than 5 lines why it is important to wear sunscreen. (Even though some

of you dont)

3, Give 3 frequencies of your choice electromagnetic wave and calculate its wavelength.

onus QuestionContinuing from question 3, supposed you where Albert Einstein and you where yet to write

your theory of Special Relativity and you asked yourself this question, if I was a beam of light

travelling at the speed of light = 3 1 08 would I see things around me moving slowor fast relative myself? Explain your answer in no less than 10 lines sound physics

explanation will be given full marks regardless of your argument

To help you understand in Special Relativity, Albert Einstein believed that physics should besimple in such a way that when you explain it to a 4 year old he or she should understand

what youre talking about. So this is what he said to explain his theory.

If two objects move in the same direction with Finitespeeds then you subtract their speeds

If two objects move in opposite directions with Finitespeeds then you add their speeds

This test is not bad as you think!!! The bonus question is the easiest question of them all,itjust needs you to think like a Physicist!!