8. The cross-bar of a rugby goal post is 3.0 m above the ground. In a training, the ball is kicked from a distance of 22 m from the goal post. The ball leaves the ground at an angle of \( 45^{\circ} \) and just goes over the cross-bar as shown in the figure below. Calculate the initial speed of the ball when it is kicked.

7. माध्यावस्था पर सरल आवर्ती दोलनक की स्थितिज ऊर्जा 20 J है ओ चरम स्थिति पर 100 J है । तो माध्य स्थिति पर गतिज ऊर्जा है- \( \begin{array}{llll}\text { (1) } 120 \mathrm{~J} & \text { (2) } 100 \mathrm{~J} & \text { (3) } 80 \mathrm{~J} & \text { (4) } 20 \mathrm{~J}\end{array} \)

3) One of the following is not a source of magnetostatic fields: A dc current in a wire An electric field linearly changing with time A permanent magnet A charged disk rotating at uniform speed

8. Am Sporttag rennen Melanie und Stefanie gemeinsam den 200-Meter-Laut. Melanie legt 80 m in 14 s zurück und Stefanie braucht für 30 m 6 s . Beide halten ihre Geschwindigkeit während des ganzen Laufes ein. Wie viele Meter vom Ziel entfernt ist Stefanie, wenn Melanie die Ziellinie erreicht?

2) By saying that the electrostatic field is conservative, we do not mean that All Choices Are Wrong The potential difference between any two points is zero. lts circulation is identically zero. Its curl is identically zero. It is the gradient of a scalar potential.

Ответ: 2,4 13 Небольшой предмет расположен на главной оптической оси тонкой собираюшей линзы с фокусным расстоянием 20 cm . Расстояние от линзы до предмета составляет 40 cm . Определите расстояние от линзы до изображения предмета. Ответ: