Plug variables expressed in SI units in the kinematic equation given in article: a = -v0^2/(2sg). What value of g you get as expressed in g’

Question

Plug variables expressed in SI units in the kinematic equation given in article: a = -v0^2/(2sg). What value of g you get as expressed in g’s where g = 9.8 m/s^2 1 point the same as in English units smaller larger this calculation cannot be performed in SI units If the initial velocity of player is doubled then the absolute acceleration would * 1 point decrease 2x stays the same increase 2x increase 4x If stopping distance is decreased 2x then the acceleration would * 1 point decrease 2x stay the same increase 2x increase 4x Other: Hockey player having initial velocity 20 m/s and helmet having padding 5 cm hits head on his twin brother. The acceleration of his brain is most closely equal to * 1 point 0.4g 4g 40g 400g

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Khang Minh 3 years 2021-07-22T21:47:34+00:00 1 Answers 15 views 0

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  1. thienan
    0
    2021-07-22T21:49:30+00:00
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    Answer:

    1) acceleration is increased by a factor of four 4X

    2) the acceleration increases a factor of 2X

    3) the correct answer of 400g

    Explanation:

    This is a kinematics exercise, where you use the velocity equation to obtain the acceleration, with the final velocity equal to zero.

               v² = v₀² + 2 a x

               0 = v₀² + 2 a x

               a = – v₀² / 2 x

               

    In the case of wanting to give the acceleration as a function of g, we can find the relationship between the two quantities

             a / g = – v₀² / (2 x g)

    Let’s answer the different questions about this equation

    1. The initial velocity is doubled, how much the acceleration is worth

               

           a/g = – (2v₀) 2 / 2xg

           a = 4 (-v₀² / 2xg) g

    acceleration is increased by a factor of four 4X

    2. if the stopping distance is reduced by 2, that is, x = x₀ / 2

    we substitute

            a/g = (- v₀² / 2g) 2/x

             

            a =2  (-v₀² / 2x₀g)  g

           

    therefore the acceleration increases a factor of 2X

    3. the initial velocity of the hockey player is v₀ = 20 m / s and the stopping distance is

    x = 5cm = 0.05m

    we calculate the acceleration

            a / g = – 20² / (2 0.05)

            a / g = – 4000 / g

            a / g = – 4000 / 9.8 = 408

            a = 408 g

    the correct answer of 400g, the value matches exactly if g = 10 m / s2 is taken

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )