A moving train is brought to rest within 20 seconds by applying brakes. find the initial velocity, if the retardation due to brake

Question

A moving train is brought to rest within 20 seconds by applying brakes. find the initial velocity, if the retardation due to brakes is 2 m s–²

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Kennedy 2 months 2021-07-27T22:53:16+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-07-27T22:54:21+00:00

    Understanding the question: This question says that we have to find out the initial velocity if a moving train is brought to rest within 20 seconds by applying brakes. And the retardation due to brakes is {\sf{2 \: ms^{-2}}} Let’s do it!

    Given that:

    • Final velocity = {\sf{0 \: ms^{-1}}}
    • Acceleration = {\sf{-2 \: ms^{-2}}}
    • Time taken = 20 seconds

    Don’t be confused!

    • Final velocity came as zero because moving train is brought to rest.

    • Acceleration came in negative beacuse the train retards.

    To calculate:

    • The initial velocity

    Solution:

    • The initial velocity = 40 m/s

    Using concept:

    • First law of motion

    Using formula:

    • v = u + at

    Where, v denotes final velocity , u denotes initial velocity , a denotes acceleration and t denotes time.

    Full Solution:

    → v = u + at

    → 0 = u + (-2)(20)

    → 0 = u + (-40)

    → 0 = u – 40

    → 0 + 40 = u

    → 40 = u

    → u = 40 m/s

    → Initial velocity = 40 m/s

    0
    2021-07-27T22:54:37+00:00

    Answer:

    Please mark as brainliest...

    Step-by-step explanation:

    v = u + at

    0 = u + (-2)(20)

    0 = u + (-40)

    0 = u – 40

    0 + 40 = u

    40 = u

    u = 40 m/s

    Initial velocity = 40 m/s

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