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3 years ago

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Strzała o masie 20g tuz po wystrzale ma prędkość 50m/s. Oblicz pracę wykonana przez zawodniczkę. Ile wynosi energia potencjalna

sprężystości napiętej cięciwy?

1 answer:

garri49 [273]3 years ago

6 0

Answer:

Explanation:

masie m = 20g = 20/1000 = 0.02kg

prędkość v = 50m/s

P.E = K.E = ½mv²

P.E = ½ × 0.02 × 50²

P.E = 25 J

pracę wykonana = P.E = 25J

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The question gave no information about the distance that the car has travelled before it skidded. However, information about the angular displacement is indeed available: the car travelled (without skidding) one-quarter of a circle, which corresponds to $90^\circ$ or $\displaystyle \frac{\pi}{2}$ radians.

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$v^2 - u^2 = 2\, a_{T}\cdot x$ .

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$\left(\omega(\text{final})\right)^2 - \left(\omega(\text{initial})\right)^2 = 2\, \alpha\, \theta$ .

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$\begin{aligned}\omega(\text{final}) &= \sqrt{2\cdot \frac{a_T}{r} \cdot \frac{\pi}{2}} = \sqrt{\frac{\pi\, a_T}{r}}\end{aligned}$ .

Let $m$ represent the mass of this car. The centripetal force at this moment would be:

$\begin{aligned}F_C &= m\, \omega^2\, r \\ &=m\cdot \left(\frac{\pi\, a_T}{r}\right)\cdot r = \pi\, m\, a_T\end{aligned}$ .

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