Physics, asked by psbhanu21, 19 days ago

A uniformly accelerated bus passes over a straight bridge of length 4.2 km. With what velocity should the bus enter the bridge in order to leave the bridge with a velocity of 29 metre per second in 4 minutes?

Please answer with correct step by step explaination. ​

Answers

Answered by yogeshgangwar044
2

Answer:

The bus should enter with velocity 6 m/sec

Explanation:

given in question

length of bridge  S = 4.2 km = 4200 m

final  velocity at the end of bridge V = 29 m/sec

time taken t = 4 minutes = 240 sec

now first we find acceleration of bus by first equation of motion

v = u + at

a = (v - u ) / t

a = (29-u)/240        (1)

now second equation of motion

s = u t + 1/2 at²

put all values

4200 = 240 u + 1/2 ((29-u)/240) ×240×240

solving this

4200 = 240(u+ 29/2 + u/2)

105/6 = u/2 +29/2

105/6 - 29/2 = u/2

18/6 = u/2

3 = u/2

so

u = 6 m/ sec

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