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Diano4ka-milaya [45]
3 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]3 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]3 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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Answer:

(a). Check attachment.

(b). 280.305 J.

(c). 31.81 kpa; 38.26K.

(d). 24.05K.

(e). 24.05k; 40kpa.

(f). -138.6J.

Explanation:

(a). Kindly check the attached picture for the diagram showing the four process.

1 - 2 = adiabatic expansion process.

2 - 3 = Isochoric process.

3 - 4 = isothermal process.

4 - 1 = isochoric process.

(b). Recall that the process from 1 to is an adiabatic expansion process.

NB: b = 5/3 for a monoatomic gas.

Then, the workdone = (1/ 1 - 1.66) [ (p1 × v1^b)/ v2^b × v2 - (p1 × v1)].

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(c). P2 = P1 × V1^b/ V2^b = 101 × 5^5/3/ 10^5/3 = 31.81 kpa.

T2 = P2 × V2/ R × 1 = 31.81 × 10/ 8.324 = 38.36k.

(d). The process 2 - 3 is an Isochoric process, then;

T3 = T2/P2 × P3 = 38.26/ 31.82 × 20 = 24.05K.

(e). The process 3 - 4 Is an isothermal process. Then, the temperature at 4 will be the same temperature at 3. Tus, we have the temperature; point 3 = point 4 = 24.05k.

The pressure can be determine as below;

P4 = P3 × V3/ V4 = 20 × 10/ 5 = 200/ 5 = 40 kpa.

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m_a_m_a [10]

The answer is n= 6.

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