2. A ball is thrown vertically upward with a velocity of \( 20 \mathrm{~m} / \mathrm{s} \) from the top of a building. The height of the point from where the ball is thrown is 25 m from the ground. (a) how high will the ball rise? (b) how long will it take for the ball to hit the ground? 3. A ball is dropped on the floor from a height of 10 m . It rebounds to a height of 2.5 m . If the ball is in contact with the floor for 0.01 sec , what is the average acceleration during contact? 4. If a stone is thrown vertically downward into a well with a speed of \( 10 \mathrm{~m} / \mathrm{s} \), how long will it take it to reach the water surface 60 m below?

body placed on a rough horizontal level \( W=75 \mathrm{~N} \) horizontal force affected 50 N Makes it about to move en the coefficient of friction equals \( \begin{array}{llll}\text { 1) } \frac{1}{3} & \text { 2) } \frac{2}{3} & \text { 3) } \frac{3}{4} & \text { 4) } \frac{1}{4}\end{array} \)

4. When you descend in a plane, your ears pop. Is air moving into your ears or out of them when they pop? 5. Explain why a balloon gets bigger as you put more molecules of gas into it at a constant temperature.

Question 6/13An air tank is exposed to ambient temperature.If you set the air pressure of the tank to 35 psi for a leak test and find that 24 hours later the tank's pressure has increased, what could've happened?The tank leakedThe tank drew in additional airThe ambient temperature increasedThe ambient temperature decreased

Prequnta 3 (4 puntos) Calcular la variación de la energia interna de un bloque de hielo de 520 g que se se encuentra \( 0{ }^{\circ} \mathrm{C} \) y a presionn atmostérica, so funde y luego se calienta a \( 4{ }^{\circ} \mathrm{C} \). Densidad del hielo \( 0.917 \mathrm{~g} / \mathrm{cm}^{3} \), calor latente de fusión \( 3.34 \times 10^{5} \mathrm{~J} / \mathrm{kg} \), densidad del agua a \( 4{ }^{\circ} \mathrm{C} \) es \( 1 \mathrm{~g} / \mathrm{cm}^{3} \).

b. Un moteur consomme \( x \) litres d'essence de masse volumique \( \rho \) et de pouvoir énergétique en \( h \) heures. 1. Quelle est la puissance \( P \) de ce moteur? 2. Trouverais-tu une valeur plus faible ou plus élevée si tu tenais compte des pertes d'énerg c. Un thermoplongeur de puissance \( P \) permet de chauffer une masse \( m \) de liquide de chaleul massique c de la température \( T_{1} \) à \( T_{2} \) en un temps \( t \). 1. Exprime la masse de liquide chauffée par ce thermoplongeur. 2. Exprime la température \( T_{2} \) du liquide.