Question

always use significant figure rules. remember that these rules apply to all numbers that are measurements.
if an object is thrown in an upward direction from the top of a building 160 ft. high at an initial speed of 21.82 mi/h., what
is its final speed when it hits the ground? (disregard wind resistance. round answer according to significant figures and
do not reflect negative direction in your answer
ft/s
106
80
70

Explanation:

Step1: Convertir la velocidad inicial a pies por segundo

La conversión de millas por hora a pies por segundo es \(1\ mi/h=\frac{5280}{3600}\ ft/s = 1.4667\ ft/s\).
Si \(v_0 = 21.82\ mi/h\), entonces \(v_0=21.82\times1.4667\ ft/s\approx32.0\ ft/s\)

Step2: Usar la ecuación de movimiento \(v^{2}=v_{0}^{2}+2gh\)

Donde \(g = 32\ ft/s^{2}\) (aceleración debido a la gravedad) y \(h = 160\ ft\) (altura del edificio).
Sustituir los valores: \(v^{2}=(32.0)^{2}+2\times32\times160\)
\(v^{2}=1024 + 10240\)
\(v^{2}=11264\)

Step3: Calcular \(v\)

Tomar la raíz cuadrada de \(v^{2}\): \(v=\sqrt{11264}\approx106\ ft/s\)

Answer:

\(106\ ft/s\)