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Diano4ka-milaya [45]
2 years ago
14

Find the time taken if the speed of a train increased rom 72km/h to 90km/h for 234km

Physics
2 answers:
bagirrra123 [75]2 years ago
8 0

Answer:

Explanation:

s = s₀ + v₀t + ½at²

Let s₀ = 0 be the position in km where acceleration starts,

Let t be in hours

a = (90 - 72) / t = 18/t  km/hr²

234 = 0 + 72t + ½(18/t)t²

234 = 72t + 9t

234 = 81t

t = 2.88888... ≈ 2.89 hr

Katarina [22]2 years ago
7 0

Answer:

2.89 hours

Explanation:

given :

Vo = 72 km/h

Vt = 90 km/h

S = 234 km

find : the time taken (t) = ?

solution :

2.a.s = Vt² - Vo²

2.a.(234) = 90²- 72²

468.a = 8100 - 5184

= 2916

a = 2916/468 = 6.23 km/h²

so,

t = (Vt-Vo) /a

= (90-72)/ 6.23

= 18/ 6.23

= 2.89 hours

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Every object has thermal energy (better word than heat, since we associate that with high temperatures). This is actually the molecules vibrating, moving a lot. More thermal energy means more vibrating, and thus also expanding in volume.
8 0
3 years ago
On Venus, the acceleration due to gravity is 8.87 m / s 2 . How far would a 17 g rock fall from rest in 6.5 s if the only force
algol [13]

Answer:

187.38 m

Explanation:

Using the equation of motion

s = ut + 1/2gt²...................... Equation 1

Where s = distance of fall, u = initial velocity of the rock, t = time taken for the rock to fall from rest, g = acceleration due to gravity of venus.

Given: u = 0 m/s ( from rest), t = 6.5 s, g = 8.87 m/s².

substituting into equation 1

s = 0(6.5) + 1/2(8.87)(6.5)²

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Hence the rock will fall 187.38 m

7 0
3 years ago
Para el siguiente conjunto de medidas, calcule EL ERROR RELATIVO PORCENTUAL: 1.34 m, 1.35 m, 1.37 m y 1.36 m
ivanzaharov [21]

Answer:

Ver explicacion abajo

Explanation:

En este caso para poder calcular el error relativo porcentual, es necesario calcular primero el error absoluto, que se calcula de la siguiente forma:

Error absoluto = Resultado exacto - aproximación

Sin embargo, no tenemos el resultado exacto de las medidas, pero podriamos conocerlo tomando el promedio de estas medidas y este es el que tomaremos como el verdadero resultado de las medidas:

Promedio de medidas = 1.34 + 1.35 + 1.37 + 1.36 / 4

Promedio de medidas = 1.355 m

Ya que tenemos el promedio, podemos calcular el error absoluto de cada medida y luego el error relativo porcentual:

Ea1 = 1.355 - 1.34 = 0.015

Ea2 = 1.355 - 1.35 = 0.005

Ea3 = 1.37 - 1.355 = 0.015

Ea4 = 1.36 - 1.355 = 0.005

Ya que tenemos los 4 errores absolutos, es posible calcular el porcentual:

%error relativo = (Error absoluto / resultado exacto) * 100

Aplicando la expresión con cada uno de los valores tenemos:

%Er1 = (0.015/1.34) * 100 = 1.12%

%Er2 = (0.005/1.35) * 100 = 0.37%

%Er3 = (0.015/1.37) * 100 = 1.09%

%Er4 = (0.005/1.36) * 100 = 0.37%

Espero que te sirva.

4 0
2 years ago
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