A car starts from rest and accelerates uniformly in a straight line in the positive x direction. After 25 seconds, its speed is 90 km/h.

Question

A car starts from rest and accelerates uniformly in a straight line in the positive x direction. After 25 seconds, its speed is 90 km/h.
a) Determine the acceleration of the object. [5]
b) How far does the object travel during the first 25 seconds? [3]
c) What is the average velocity of the object during the first 25 seconds?

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Yến Oanh 2 months 2021-07-24T20:10:28+00:00 1 Answers 3 views 0

Answers ( )

    0
    2021-07-24T20:11:34+00:00

    Answer:

    A. 1 m/s²

    B. 312.5 m

    C. 12.5 m/s

    Explanation:

    We’ll begin by converting the velocity i.e 90 Km/h to m/s. This can be obtained as follow:

    Velocity (Km/h) = 90 Km/h

    Velocity (m/s) =?

    Velocity (m/s) = Velocity (Km/h) × 1000 / 3600

    Velocity (m/s) = 90 × 1000 / 3600

    Velocity (m/s) = 90000 / 3600

    Velocity (m/s) = 25 m/s

    A. Determination of the acceleration.

    Initial velocity (u) = 0 m/s

    Final velocity (v) = 25 m/s

    Time (t) = 25 s

    Acceleration (a) =?

    v = u + at

    25 = 0 + (a × 25)

    25 = 0 + 25a

    25 = 25a

    Divide both side by 25

    a = 25/25

    a = 1 m/s²

    B. Determination of the distance travelled.

    Initial velocity (u) = 0 m/s

    Final velocity (v) = 25 m/s

    Acceleration (a) = 1 m/s²

    Distance travelled (s) =?

    v² = u² + 2as

    25² = 0 + (2 × 1 × s)

    625 = 0 + 2s

    625 = 2s

    Divide both side by 2

    s = 625 / 2

    s = 312.5 m

    C. Determination of the average velocity.

    Total distance travelled = 312.5 m

    Total time = 25 s

    Average velocity =?

    Average velocity = Total distance / total time

    Average velocity = 312.5 / 25

    Average velocity = 12.5 m/s

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