Ask Question
9 September, 01:00

Jay rides his 2.0-kgkg skateboard. He is moving at speed 5.8 m/sm/s when he pushes off the board and continues to move forward in the air at 5.4 m/sm/s. The board now goes forward at 13 m/sm/s. Part APart complete Determine Jay's mass. Express your answer to two significant figures and include the appropriate units. mJmJ = 36 kgkg SubmitPrevious Answers Correct Part B Determine the change in the internal energy of the system during this process.

+2
Answers (1)
  1. 9 September, 01:19
    0
    36 kg, - 54.72 J

    Explanation:

    Part A.

    From the general momentum equation we have that:

    Pji + Psi + Jonj + Jons = Pjf + Psf

    Let's just consider the x axis:

    Pjix + Psix + Jx = Pjfx + Psfx

    Pjix = Mj * vix

    Psix = Ms * vix

    Mj = what we want to know

    Ms = 2 kg

    vix = 5.8 m / s

    Jx = 0

    Pjfx = Mj * vjfx

    Psfx = Ms * vsfx

    vsfx = 13 m / s

    vjfx = 5.4 m / s

    By replacing all these values we are left with:

    Mj * 5.8 + 2 * 5.8 + 0 = 5.4 * Mj + 2 * 13

    0.4 * Mj = 26 - 11.6

    Mj = 14.4 / 0.4

    Mj = 36 kg

    Part B.

    If we apply the generelized work energy principle we have to:

    Ui + W = Uf

    Ki + 0 = Kf + Uint

    Ki = 1/2 * (Mj + Ms) * vix ^ 2

    All known values, if we replace we have:

    Ki = (1/2) * (36 + 2) * (5.8 ^ 2)

    Ki = 639.16

    Kf = 1/2 * (Mj * vjfx ^ 2 + Ms * vsfx ^ 2)

    Replacing the values, we are left with:

    Kf = 1/2 * (36 * (5.4) ^ 2 + 2 * (13 ^ 2))

    Kf = 693.88

    Replacing in:

    Ki + 0 = Kf + Uint

    Uint = Ki - Kf

    Uint = 639.16 - 693.88

    Uint = - 54.72

    The internal energy is - 54.72 Jules
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Jay rides his 2.0-kgkg skateboard. He is moving at speed 5.8 m/sm/s when he pushes off the board and continues to move forward in the air ...” in 📙 Physics if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers