A 2 kg body is dropped from a height of 3 m. Calculate: to. The speed of the body when it is 1 m high b. The speed o

Question

A 2 kg body is dropped from a height of 3 m. Calculate:

to. The speed of the body when it is 1 m high

b. The speed of the body when it reaches the ground

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Ngọc Hoa 4 years 2021-09-05T11:18:21+00:00 1 Answers 5 views 0

Answers ( )

  1. thanhha
    0
    2021-09-05T11:19:51+00:00
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    Answer:

       a) 6.26 m/s

       b) 7.67 m/s

    Explanation:

    The potential energy at height h0 is initially …

      PE0 = mgh0

    At height h1, the potential energy is …

      PE1 = mgh1

    The difference in potential energy is converted to kinetic energy:

      PE0 -PE1 = KE1 = (1/2)m(v1)^2

    Solving for v1, we have …

      mg(h0 -h1) = (1/2)m(v1)^2

      2g(h0 -h1) = (v1)^2

      v1 = √(2g(h0 -h1))

    __

    a) When the body is 1 m high, its speed is …

      v = √(2(9.8)(3 -1)) ≈ 6.26 m/s . . . at 1 m high

    __

    b) When the body is 0 m high, its speed is …

      v = √(2(9.8)(3 -0)) ≈ 7.67 m/s . . . when it reaches the ground

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