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zepelin [54]
3 years ago
6

Un auto se mueve con velocidad constante de 20 m/s y la mantiene durante 20 s. Después se le aplica una aceleración constante y

aumenta su velocidad a 40 m/s, recorriendo durante el cambio de velocidad una distancia de 200 m ¿Cuál es el tiempo empleado en el recorrido total?
Physics
1 answer:
pentagon [3]3 years ago
4 0

Answer:

26.67 s

Explanation:

v = Velocidad final = 40 m/s

u = Velocidad inicial = 20 m/s

t_1 = Tiempo inicial = 20 s

t_2 = Tiempo empleado durante la aceleración

a = Aceleración

s = Desplazamiento del automóvil durante la aceleración = 200 m

De las ecuaciones lineales de movimiento tenemos

v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{40^2-20^2}{2\times 200}\\\Rightarrow a=3\ \text{m/s}^2

v=u+at_2\\\Rightarrow t_2=\dfrac{v-u}{a}\\\Rightarrow t_2=\dfrac{40-20}{3}\\\Rightarrow t_2=6.67\ \text{s}

El tiempo necesario para acelerar es 6.67 s

El tiempo total necesario para toda la ruta es t=t_1+t_2=20+6.67=26.67\ \text{s}.

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