Exercice 12 Placé dans un champ électrostatique uniforme horizontal, un pendule électrostatique porte une boule chargée positivement, de dimensions négligeables et de masse \( \mathrm{m}=5 \mathrm{~g} \). Le fil s'écarte d'un angle \( \alpha=20^{\circ} \) de la verticale. La charge de la boule vaut \( q=1 \mu C \). On donne \( \mathrm{g}=10 \mathrm{~N} / \mathrm{Kg} \). 1) Fais le bilan des forces qui s'exercent sur la boule. 2) Calcule l'intensité de la force électrique. 3) Détermine les caractéristiques du champ électrostatique 4) Fais un schéma et dessine de façon approximative

Un cubo de oro se sumerge totalmente en hidrógeno. Si tiene un peso con una magnitud de \( 32,93 \mathrm{~N} \) ¿Cuál es el volumen del fluido desalojado? \( \begin{array}{l}\text { a. } 47,29 \mathrm{~m}^{\wedge} 3 \\ \text { b. } 375 \mathrm{~m}^{\wedge} 3 \\ \text { c. } 37,29 \mathrm{~m}^{\wedge} 3\end{array} \)

Se sumerge un cubo de hierro en un fluido, el peso de este es de \( 85,38 \mathrm{~N} \) y el volumen es de \( 32,7 \mathrm{~m}^{\wedge} 3 \) ¿Cuál es la densidad del fluido en cuestión? a. \( 0,26 \mathrm{~kg} / \mathrm{m}^{\wedge} 3 \) b. \( 1,26 \mathrm{~kg} / \mathrm{m}^{\wedge} 3 \) c. \( 0,98 \mathrm{~kg} / \mathrm{m}^{\wedge} 3 \)

11 in the blanks : (i) A body is said to be in motion if it ...... its position with respect to its surroundings. (ii) A body is said to be at ...... at an instant if its position with respect to the surrounding objects remains unchanged during that instant. (iii) The ...... of a body is defined as the rate of change of its position with respect to its surroundings irrespective of direction. (iv) Speed is a ...... quantity. (v) The ..... of a body is the rate of change of its position with respect to its surroundings in a particular direction. (vi) Velocity is ...... quantity. (vii) If a body travels equal distances in equal intervals of time in the same direction it is said to be moving with a ..... velocity. (viii) The rate of change of velocity of a body is called its...... (ix) The ..... velocity of a body is the velocity with which the distance travelled by the body in the same interval of time is the same as with variable velocity. (x) If the velocity of a body changes by equal amounts in equal intervals of time, the body is said to move with ...... (xi) If the velocity of a body changes by unequal amounts in equal intervals of time, the body is said to move with ...... .

Su una portaerei un jet viene catapultato da \( 0 \mathrm{~km} / \mathrm{h} \) a \( 240 \mathrm{~km} / \mathrm{h} \) in \( 2,00 \mathrm{~s} \). Se la forza media esercitata dalla catapulta è \( 9,35 \cdot 10^{5} \mathrm{~N} \), qual è la massa del jet?

A sensitive galvanometer, the maximum curent that its coil can measure is \( 5 \mathrm{~m} / \), and when it is used to measure an electne current of intensity \( 2 \times 10^{\prime} 1 \mathrm{LA} \) its pointer deflects by an angle \( 30^{\circ} \), so the maximum angle of deflection of the galvanometer pointer from zero position is .......... (A) \( 25^{\circ} \) (B) \( 50^{\circ} \) (C) \( 75^{\circ} \) (D) \( 90^{\circ} \)