A bullet is fired through a board, 14.0 cm thick, with its line of motion perpendicular to the face of the board. If it enters with a speed

Question

A bullet is fired through a board, 14.0 cm thick, with its line of motion perpendicular to the face of the board. If it enters with a speed of 450 m/s and emerges with a speed of 220 m/s, what is the bullet’s acceleration as it passes through the board, in units of km/s2 , assuming constant acceleration?

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Thạch Thảo 4 years 2021-08-31T16:07:15+00:00 1 Answers 196 views 0

Answers ( )

  1. Doris
    -1
    2021-08-31T16:08:48+00:00
    Reply

    Answer:

    a=-550.35\ m/s^2.

    Explanation:

    Given :

    Thickness of board , d=14 \ cm =\dfrac{14}{100000}\ km=1.4\times 10^{-4}\ km.

    Initial speed of bullet , u=450\ m/s=\dfrac{450}{1000}\ km/s=0.45\ km/s.

    Final speed of bullet , v=220\ m/s=\dfrac{220}{1000}\ km/s=0.22\ km/s.

    We know by equation of motion.

    v^2-u^2=2as  ( all sign have their usual meaning )

    Putting all given values we get :

    0.22^2-0.45^2=2\times a\times 1.4\times 10^{-4}\\\\\dfrac{0.22^2-0.45^2}{2\times 1.4\times 10^{-4} }=a\\\\

    a=-550.35\ m/s^2.

    Hence, this is the required solution.

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