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On a see-saw Mary, weight 600N balances John, weight 200N when she sits 1.5m away from the pivot. How far from the pivot is John?

Using the knowledge that the moments are balanced, we can create an equation to calculate the distance John is from the pivot: 600N 1.50m = 200N (distance) (600/200)*1.5 = distance distance = 4.5m
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Answered by Alexander N. Physics tutor
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The loudspeaker produces a sound wave with a frequency of 850 hertz and a wavelength of 0.4 metres. Calculate the speed of this sound wave. Give the unit

The speed of a wave is given by "Frequency*Wavelength=Wave speed". Hence, the speed is 340. With the units of speed being m/s
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Answered by Alexander N. Physics tutor
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How do I write a good introduction to an essay?

The introduction to your English essay is all about opening up, clearing up and getting your readers prepared for the nature of your answer. In other words, the introduction should warm your reader up to the...
MF
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How do you differentiate y = 5 x^3 + 1/2 x^2 + 3x -4

FIrslty to avoid confusion: x = the variable x X = multiplication. When you differentiate an equation, the derivative (answer) is referred to as dy/dx. For a polynomial as in this question you take each term...
EM
Answered by Emma M. Maths tutor
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When using the addition rule in probability, why must we subtract the "intersection" to find the "union" with the Addition Rule?

There is a subtle point to be made here, which comes down to double counting. The addition rule:Pr(A union B) = Pr(A)+Pr(B)-Pr(A intersection B)allows us to work out the probability that either event A or ev...
LG
Answered by Lewis G. Maths tutor
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