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?

2) ¿Qué aceleración adquiere si se le aplica el doble de fuerza que en el punto anterior? ¿Y si se le aplica el triple? Hacé los cálculos aplicando la fórmula, luego justificalo a través del enunciado de la Segunda Ley.

f Steve throws the football 50 meters in 3 seconds, what is the average speed of the football? (nearest hundredth) If it takes Ashley 3 seconds to run from the batters box to first base at an average spe of 6.5 meters per second, what is the distance she covers in that time? \( \begin{array}{l}\text { Bart ran } 5000 \text { meters from the cops and an average speed of } 8 \text { meters/second before } \\ \text { he got caught. How long did he run? }\end{array} \)

85 Un pannello di MDF, una fibra di legno utilizzata per mobili componibili, ha spessore \( (14,0 \pm 0,2) \mathrm{mm} \) e forma rettangolare con lati \( (60,0 \pm 0,1) \mathrm{cm} \) e \( (80,0 \pm 0,1) \mathrm{cm} \); la sua massa è \( (5600 \pm 20) \mathrm{g} \). Le specifiche del prodotto in- dicano che il materiale ha densità \( 850 \mathrm{~kg} / \mathrm{m}^{3} \), con tolle- ranza dell' \( 1 \% \). Calcola la densità del pannello in base ai valori mi- surati.

Sloths are known for being slow. An average tree sloth moves at a speed of \( 0.743 \mathrm{~m} / \mathrm{s} \). T the nearest second, how long does it take a sloth to travel 22.3 m at this speed?

Dados los vectores \( \vec{P}=(1 \hat{i}-2 \hat{j}) m \) y \( \vec{Q}=(-9 \hat{i}+20 \hat{j}) m \), el vector resultante de la suma \( \vec{P}+\vec{Q} \) es: