A projectile is fired vertically upwards and reaches a height of 78.4 m. Find the velocity of projection and the time it takes to reach its

Question

A projectile is fired vertically upwards and reaches a height of 78.4 m. Find the velocity of projection and the time it takes to reach its highest point.

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Thu Giang 5 years 2021-08-27T19:58:17+00:00 1 Answers 13 views 0

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  1. binhan
    0
    2021-08-27T19:59:46+00:00
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    Answer:

    1.) U = 39.2 m/s

    2.) t = 4 seconds

    Explanation: Given that the

    height H = 78.4m

    The projectile is fired vertically upwards under the acceleration due to gravity g = 9.8 m/s^2

    Let’s assume that the maximum height = 78.4m. And at maximum height, final velocity V = 0

    Velocity of projections can be achieved by using the formula

    V^2 = U^2 – 2gH

    g will be negative as the object is moving against the gravity

    0 = U^2 – 2 × 9.8 × 78.4

    U^2 = 1536.64

    U = sqrt( 1536.64 )

    U = 39.2 m/s

    The time it takes to reach its highest point can be calculated by using the formula;

    V = U – gt

    Where V = 0

    Substitute U and t into the formula

    0 = 39.2 – 9.8 × t

    9.8t = 39.2

    t = 39.2/9.8

    t = 4 seconds.

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