The small washer is sliding down the cord OA. When it is at the midpoint, its speed is 28 m/s and its acceleration is 7 m/s 2 . Express the velocity and acceleration of the washer at this point in terms of its cylindrical components.

Answer :

Chrisnando

Answer:

Velocity components

[tex] V_r = -16.28 m/s [/tex]

[tex] V_z = -22.8 m/s [/tex]

[tex] V_q = 0 m/s [/tex]

For Acceleration components;

[tex] a_r = -4.07m/s^2 [/tex]

[tex] a_z = -5.70m/s^2 [/tex]

[tex] a_q = 0m/s^2 [/tex]

Explanation:

We are given:

[tex] Speed v_o = 28 m/s [/tex]

[tex] Acceleration a_o= 7 m/s^2[/tex]

We first need to find the radial position r of washer in x-y plane.

Therefore

[tex] r = \sqrt{300^2 + 400^2} [/tex]

r = 500 mm

To find length along direction OA we have:

[tex] L = \sqrt{500^2 + 700^2}

L = 860 mm [/tex]

Therefore, the radial and vertical components of velocity will be given as:

[tex] V_r = V_o*cos(Q) [/tex]

[tex] V_z = V_o*sin(Q) [/tex]

Where Q is the angle between OA and vector r.

Therefore,

[tex] V_r = 28 * \frac{r}{L} = > 28 * \frac{500}{860} [/tex]

[tex] V_r = -16.28 m/s [/tex]

• [tex] V_z = 28 * \frac{700}{860} = -22.8 [/tex]

• [tex] V_q = 0 m/s [/tex]

The radial and vertical components of acceleration will be:

[tex] a_r = a_o*cos(Q) [/tex]

[tex] a_z = a_o*sin(Q) [/tex]

Therefore we have:

• [tex] a_r = 7* \frac{500}{860} = -4.07m/s^2 [/tex]

• [tex] a_z = 7 * \frac{700}{860} = -5.70 m/s^2 [/tex]

• [tex] a_q = 0 m/s^2 [/tex]

Note : image is missing, so I attached it

${teks-lihat-gambar} Chrisnando
${teks-lihat-gambar} Chrisnando

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