Question

always use significant figure rules. remember that these rules apply to all numbers that are measurements. a penny falls from a windowsill which is 25.0 m above the sidewalk. how much time does a passerby on the sidewalk below have to move out of the way before the penny hits the ground? s 2.26 1.0 5.10

Explanation:

Step1: Identificar la ecuación

Utilizamos la ecuación $h = v_0t+\frac{1}{2}gt^2$. Dado que la moneda cae desde el reposo, $v_0 = 0$. Entonces la ecuación se convierte en $h=\frac{1}{2}gt^2$.

Step2: Despejar el tiempo

Despejando $t$ de $h=\frac{1}{2}gt^2$, obtenemos $t=\sqrt{\frac{2h}{g}}$. Sabemos que $h = 25.0$ m y $g = 9.8$ m/s².

Step3: Calcular el tiempo

Sustituimos los valores: $t=\sqrt{\frac{2\times25.0}{9.8}}=\sqrt{\frac{50.0}{9.8}}\approx\sqrt{5.102}\approx 2.26$ s.

Answer:

2.26 s