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3 years ago

8

What is the speed of a ball that is attached to a string and swings in a horizontal circle of radius 2.0 m with the central acce

leration of 15 m/s^2?

1 answer:

Ira Lisetskai [31]3 years ago

7 0

Answer:

5.48 m/s.

Explanation:

Use the formula a=v^2/r.

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2 years ago

a resistor, of resistance 47 , is damaged when it dissipates a power greater than 0.5W. determine the maximum voltage that can b

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Answer:

<em>The maximum voltage that can be applied without damaging the resistor is 4.85 V</em>

Explanation:

<u>Electric Power in a Resistor</u>

Given a resistor or resistance R connected to a circuit of voltage V carrying a current I. The relation between these three magnitudes is given by Ohm's Law:

V = R.I

The dissipated power P of a resistor can be calculated by the following equation, known as Joule's first law:

$P = I^2.R$

Solving the first equation for I:

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Substituting in the second equation:

$\displaystyle P=\frac{V^2}{R^2}.R$

Simplifying:

$\displaystyle P=\frac{V^2}{R}$

Solving for V:

$V=\sqrt{P.R}$

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$V=\sqrt{0.5\cdot 47}$

$V=\sqrt{23.5}$

V = 4.85 V

The maximum voltage that can be applied without damaging the resistor is 4.85 V

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