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A train with an initial velocity of 20ms-1 is subjected to a uniform deceleratio...


Question

A train with an initial velocity of 20ms-1 is subjected to a uniform deceleration of 2ms-2. The time required to bring the train to a complete halt is

Options

A) 10s

B) 40s

C) 5s

D) 20s


The correct answer is A.

Explanation:

We have been given:
final velocity = \(v = 0\text{m/s}\), initial velocity = \(u = 20\text{m/s}\), deceleration = \(a = -2\text{m/s}^2\) (this value is negative because it is decelerating)
\(v = u + at\)
\(0=20+(-2t)\)
\(2t=20\)
\(t=20÷2=10\text{s}\)

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Discussion (3)

  • We have been given:
    final velocity = \(v = 0\text{m/s}\), initial velocity = \(u = 20\text{m/s}\), deceleration = \(a = -2\text{m/s}^2\) (this value is negative because it is decelerating)
    \(v = u + at\)
    \(0=20+(-2t)\)
    \(2t=20\)
    \(t=20÷2=10\text{s}\)

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  • Iyanuoluwa Ajibola

    v = u + at
    where v= final velocity = 0
    u = initial velocity = 20m/s
    a = retardation = 2m/s²
    From the formula:
    v = u + at
    v - u = at
    0 - 20 = 2t
    -20 = 2t
    Divide both side by co-efficient of T
    t = -20/2
    t = 10s
    Since deceleration is negatively virtual 2
    I mean -2.

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  • Ayomide

    Given:
    \(v = 0\text{m/s}\), \(u = 20\text{m/s}\), \(a = -2\text{m/s}^2\) (the figure is carrying a negative sign because it is decelerating)
    \(v = u + at\)
    \(0=20+(-2t)\)
    \(2t=20\)
    \(t=20÷2=10\text{s}\)

    Reply
    Like