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A wheel rotates about a fixed axis with a constant angular acceleration of 3.3 rad/s2. The diameter of the wheel is 21 cm. What is the linear speed (in m/s) of a point on the rim of this wheel at an instant when that point has a total linear acceleration with a magnitude of 1.7 m/s2

Respuesta :

Answer:

The the linear speed (in m/s) of a point on the rim of this wheel at an instant=0.418 m/s

Explanation:

We are given that

Angular acceleration, [tex]\alpha=3.3 rad/s^2[/tex]

Diameter of the wheel, d=21 cm

Radius of wheel, [tex]r=\frac{d}{2}=\frac{21}{2}[/tex] cm

Radius of wheel, [tex]r=\frac{21\times 10^{-2}}{2} m[/tex]

1m=100 cm

Magnitude of total linear acceleration, a=[tex]1.7 m/s^2[/tex]

We have to find the linear speed  of a  at an instant when that point has a total linear acceleration with a magnitude of 1.7 m/s2.

Tangential acceleration,[tex]a_t=\alpha r[/tex]

[tex]a_t=3.3\times \frac{21\times 10^{-2}}{2}[/tex]

[tex]a_t=34.65\times 10^{-2}m/s^2[/tex]

Radial acceleration,[tex]a_r=\frac{v^2}{r}[/tex]

We know that

[tex]a=\sqrt{a^2_t+a^2_r}[/tex]

Using the formula

[tex]1.7=\sqrt{(34.65\times 10^{-2})^2+(\frac{v^2}{r})^2}[/tex]

Squaring on both sides

we get

[tex]2.89=1200.6225\times 10^{-4}+\frac{v^4}{r^2}[/tex]

[tex]\frac{v^4}{r^2}=2.89-1200.6225\times 10^{-4}[/tex]

[tex]v^4=r^2\times 2.7699[/tex]

[tex]v^4=(10.5\times 10^{-2})^2\times 2.7699[/tex]

[tex]v=((10.5\times 10^{-2})^2\times 2.7699)^{\frac{1}{4}}[/tex]

[tex]v=0.418 m/s[/tex]

Hence, the the linear speed (in m/s) of a point on the rim of this wheel at an instant=0.418 m/s