An ice skater rotates about a vertical axis through the center of her body. Find her angular velocity (in rad/s) if the radial acceleration at a point on the body [tex]$r = 26.0 \, \text{cm}$[/tex] from the axis of rotation is not to exceed 12.0 times gravitational acceleration [tex][tex]$g$[/tex][/tex].



Answer :

To find the angular velocity [tex]\(\omega\)[/tex] of an ice skater given that her radial acceleration at a point [tex]\( r = 26.0 \, \text{cm} \)[/tex] from the axis of rotation should not exceed 12.0 times the gravitational acceleration [tex]\( g \)[/tex], we follow these steps:

1. Convert the radius to meters:
[tex]\[ r = 26.0 \, \text{cm} = 0.26 \, \text{m} \][/tex]

2. Understand the gravitational acceleration [tex]\( g \)[/tex]:
[tex]\[ g = 9.8 \, \text{m/s}^2 \][/tex]

3. Calculate the maximum radial acceleration:
[tex]\[ \text{Maximum radial acceleration} = 12.0 \times g = 12.0 \times 9.8 \, \text{m/s}^2 = 117.6 \, \text{m/s}^2 \][/tex]

4. Use the formula for radial acceleration:
The radial acceleration [tex]\( a \)[/tex] is given by:
[tex]\[ a = \omega^2 \cdot r \][/tex]
Where, [tex]\( \omega \)[/tex] is the angular velocity.

5. Solve for angular velocity [tex]\( \omega \)[/tex]:
[tex]\[ \omega^2 = \frac{a}{r} \][/tex]
[tex]\[ \omega = \sqrt{\frac{a}{r}} \][/tex]

6. Substitute the given values:
[tex]\[ \omega = \sqrt{\frac{117.6 \, \text{m/s}^2}{0.26 \, \text{m}}} \][/tex]

7. Calculate [tex]\(\omega\)[/tex]:
[tex]\[ \omega = \sqrt{452.3076923076922} \][/tex]
[tex]\[ \omega \approx 21.27 \, \text{rad/s} \][/tex]

Thus, the angular velocity [tex]\(\omega\)[/tex] of the ice skater is approximately [tex]\( 21.27 \, \text{rad/s} \)[/tex].