A stone is thrown straight up from the edge of a roof, 850 feet above the ground, at a speed of 12 feet per second. A. Remembering that the acceleration due to gravity is -32 feet per second squared, how high is the stone 3 seconds later? B. At what time does the stone hit the ground? C. What is the velocity of the stone when it hits the ground?

Ex 26 (Pec9) จากรูป นำเชือกผูกกับก้อนน้ำหนัก \( W \) จงหาอัตราส่วนของขนาดของแรงดึงในเส้นเชือก \( T_{1} \) ต่อ \( T_{2} \) กำหนด \( \sin 53^{\circ}=4 / 5, \sin 37^{\circ}=3 / 5 \)

6. In Activity 12 , if you pull down on the DRFS sensor arm, the DRFS produces a positive reading. How can one justify the statement that the DRFS takes \( u p \) to be the positive direction for the force the spring applies to the mass? (The correct answer uses Newton's Third Law but not \( F=-k y \).)

Look at the electrical diagram. \begin{tabular}{l}\( V=8.6 \mathrm{~V} \) \\ \( I 1=0.3 \mathrm{~A} \) \\ \( I 2=0.5 \mathrm{~A} \) \\ \( I 3=0.2 \mathrm{~A} \) \\ Calculate the total resistance. \\ \hline 8.6 \\ \hline OK. \\ \( \begin{array}{l}V=10.6 \mathrm{~V} \\ I 1=0.9 \mathrm{~A} \\ I 2=0.3 \mathrm{~A} \\ I 3=0.3 \mathrm{~A}\end{array} \) \\ Calculate the total resistance. \\ \hline\end{tabular}

4) Un coche que va a \( 72 \mathrm{Km} / \mathrm{h} \), tarda 3 h y 15 minutos en hacer un recorrido. ¿Cuánto tardará otı coche en hacer el mismo recorrido si va a \( 90 \mathrm{~km} / \mathrm{h} \) ?

7.1 point A cat is sitting on a table admiring a small glass bottle located close to the table edge. Next thing, the bottle is flying off the table horizontally with a speed of \( 1.08 \mathrm{~m} / \mathrm{s} \). At what speed will the bottle hit the floor 0.69 m below the table surface? Ignore effects of air friction.