Respuesta :
Answer:
a) The angular speed of the wheel after 1.30 seconds is [tex]2.47\,\frac{rad}{s}[/tex], b) The tangential speed of the spot after 1.30 seconds is [tex]0.543\,\frac{m}{s}[/tex], c) The magnitude of the total acceleration of the spot after 1.30 seconds is [tex]1.406\,\frac{m}{s^{2}}[/tex], d) The angular position of the spot is 2.130 radians (122.011°).
Explanation:
a) Given that tire accelerates at constant rate, final angular speed can be predicted by using the following formula:
[tex]\omega = \omega_{o} + \alpha \cdot \Delta t[/tex]
Where:
[tex]\omega[/tex] - Final angular speed, measured in radians per second.
[tex]\omega_{o}[/tex] - Initial angular speed, measured in radians per second.
[tex]\alpha[/tex] - Angular acceleration, measured in radians per square second.
[tex]\Delta t[/tex] - Time, measured in seconds.
Given that [tex]\omega_{o} = 0\,\frac{rad}{s}[/tex] (starts at rest), [tex]\alpha = 1.90\,\frac{rad}{s^{2}}[/tex] and [tex]\Delta t = 1.30\,s[/tex], the final angular speed is:
[tex]\omega = 0\,\frac{rad}{s} + \left(1.90\,\frac{rad}{s^{2}} \right) \cdot (1.30\,s)[/tex]
[tex]\omega = 2.47\,\frac{rad}{s}[/tex]
The angular speed of the wheel after 1.30 seconds is [tex]2.47\,\frac{rad}{s}[/tex].
b) The tangential speed of the spot is the product of the distance between the center of the wheel and spot. That is:
[tex]v = r \cdot \omega[/tex]
Where r is the distance between the center of the wheel and spot. The tangential speed of the spot after 1.30 seconds is:
[tex]v = (0.220\,m)\cdot \left(2.47\,\frac{rad}{s} \right)[/tex]
[tex]v = 0.543\,\frac{m}{s}[/tex]
The tangential speed of the spot after 1.30 seconds is [tex]0.543\,\frac{m}{s}[/tex].
c) The magnitude of the total acceleration of the spot is the magnitude of the vectorial sum of radial and tangential accelerations (both components are perpendicular to each other), which is determined by the Pythagorean theorem, that is:
[tex]a = \sqrt{a_{r}^{2} + a_{t}^{2}}[/tex]
Where [tex]a_{r}[/tex] and [tex]a_{t}[/tex] are the radial and tangential accelerations.
[tex]a = r\cdot \sqrt{\omega^{4} + \alpha^{2}}[/tex]
If [tex]r = 0.220\,m[/tex], [tex]\omega = 2.47\,\frac{rad}{s}[/tex] and [tex]\alpha = 1.90\,\frac{rad}{s^{2}}[/tex], then, the resultant acceleration is:
[tex]a = (0.220\,m)\cdot \sqrt{\left(2.47\,\frac{rad}{s} \right)^{4}+\left(1.90\,\frac{rad}{s^{2}} \right)^{2}}[/tex]
[tex]a \approx 1.406\,\frac{m}{s^{2}}[/tex]
The magnitude of the total acceleration of the spot after 1.30 seconds is [tex]1.406\,\frac{m}{s^{2}}[/tex].
d) Let be 30° (0.524 radians) the initial angular position of the spot with respect to center. The final angular position is determined by the following equation of motion:
[tex]\omega^{2} = \omega_{o}^{2} + 2\cdot \alpha \cdot (\theta - \theta_{o})[/tex]
Final angular position is therefore cleared:
[tex]\theta - \theta_{o} = \frac{\omega^{2}-\omega_{o}^{2}}{2\cdot \alpha}[/tex]
[tex]\theta = \theta_{o} + \frac{\omega^{2}-\omega_{o}^{2}}{2\cdot \alpha}[/tex]
Given that [tex]\theta_{o} = 0.524\,rad[/tex], [tex]\omega_{o} = 0\,\frac{rad}{s}[/tex], [tex]\omega = 2.47\,\frac{rad}{s}[/tex] and [tex]\alpha = 1.90\,\frac{rad}{s^{2}}[/tex], the angular position of the spot after 1.30 seconds is:
[tex]\theta = 0.524\,rad +\frac{\left(2.47\,\frac{rad}{s} \right)^{2} - \left(0\,\frac{rad}{s}\right)^{2}}{2\cdot \left(1.90\,\frac{rad}{s^{2}} \right)}[/tex]
[tex]\theta = 2.130\,rad[/tex]
[tex]\theta = 122.011^{\circ}[/tex]
The angular position of the spot is 2.130 radians (122.011°).
In the rotational motion of an object, the angular acceleration is always towards the center, and the further discussion is as follows:
Rotational motion:
The tangential acceleration of the object keeps changing its direction as the object rotates, always directed toward the tangent of the circle passing through the position of the object.
Radius of the spot, r = 0.220
minitial angle from the horizontal, θ = 30°
angular acceleration, α = 1.9 rad/s²
(a) from the first equation of motion we get:
ω = ω₀ + αt where
ω is the final angular speed
ω₀ is the initial angular speedand
t is the time = 1.3sω = 1.9×1.3 rad/sω = 2.47 rad/s
(b) tangential speed (v) is given by:
v = r×ωv = 0.220×2.47 m/sv = 0.5434 m/s
(c) The instantaneous tangential acceleration is given by:
[tex]a_t[/tex] = rω²so the resultant acceleration will be:
[tex]a=\sqrt{a_t^2+\alpha^2}\\\\a =\sqrt{r^2\omega^4+\alpha^2}\\\\a= \sqrt{(0.220)^2(2.47)^4+(1.9)^2}\\\\a = 1.4 \ \frac{m}{s^2}[/tex]
(d)
The angular displacement is given by:
θ = θ₀t + ¹/₂αt²θ₀ = 30° = 0.524
rad θ = 0.524×1.3 + ¹/₂×1.9×1.3²θ = 2.286 radθ = 131°
Following are the solution for points:
For a)
The angular speed is 2.47 rad/s
For b)
The tangential speed is 0.5434 m/s
For c)
Total acceleration is 1.4 m/s²
For d)
The final angular position is 131°
Learn more about rotational here:
brainly.com/question/1571997
