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Physics

2 answers:

Veronika [31]3 years ago

7 0

C. Hot air balloons use convection to rise.

Law Incorporation [45]3 years ago

7 0

<span>hot air balloons rise due to convection. Hot air is less dense than cool air; the heated air causes the balloon to rise simply because it is lighter than an equal volume of cold air. the transfer of heat from flame to air is the convection process.</span>

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The maximum displacement of an oscillatory motion is A=0.49m. Determine the position x at which the kinetic energy of the partic

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Answer:

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$E_T = U +K.E\\\\E_T = \frac{1}{2} kA^2\\\\ \frac{1}{2} kA^2 = U +K.E\\\\K.E = \frac{1}{2} kA^2 - U ----equation(1)$

When the kinetic energy (E) is half of the elastic potential energy (U);

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Equate (1) and (2)

$\frac{U}{2} = \frac{1}{2} kA^2 - U\\\\U = kA^2 -2U\\\\U+2U = kA^2\\\\3 U = kA^2\\\\3(\frac{1}{2} kx^2) = kA^2\\\\\frac{3}{2} x^2=A^2\\\\x^2 = \frac{2}{3} A^2\\\\x = \sqrt{\frac{2}{3} A^2} \\\\x = A\sqrt{\frac{2}{3} } \\\\x = 0.49\sqrt{\frac{2}{3} }\\\\x = + /- (0.4 \ m)$