You are driving down the road at 15 m/s you step on the gas and speed up with uniform acceleration of 2.5 m/s^2 for 0.80 seconds. If your tires have a radius of 34 cm, what is their angular displacement during this period of acceleration?

Respuesta :

Answer:

[tex] x_f = 15 m/s *0.8 s + \frac{1}{2} 2.5 m/s^2 (0.8 s)^2 = 12.8 m[/tex]

And we have the following relation between the angular displacement and the linear displacement:

[tex] x = r \theta[/tex]

Where x represent the linear displacement and [tex]\theta[/tex] the angular displacement, if we solve for [tex] \theta[/tex] we got:

[tex] \theta= \frac{x}{R}= \frac{12.8 m}{0.34 m}=37.65 rad[/tex]

Explanation:

For this case we have the following data given:

[tex] v_i = 15 m/s[/tex] represent the initial speed

[tex] a = 2.5 m/s^2[/tex] represent the acceleration

[tex] t = 0.8 s[/tex] represent the time

[tex] R = 34 cm = 0.34 m[/tex] represent the radius

First we can calculate the linear displacement with the following formula from kinematics:

[tex] x_f = x_i + v_i t + \frac{1}{2} at^2[/tex]

And replacing we have:

[tex] x_f = 15 m/s *0.8 s + \frac{1}{2} 2.5 m/s^2 (0.8 s)^2 = 12.8 m[/tex]

And we have the following relation between the angular displacement and the linear displacement:

[tex] x = r \theta[/tex]

Where x represent the linear displacement and [tex]\theta[/tex] the angular displacement, if we solve for [tex] \theta[/tex] we got:

[tex] \theta= \frac{x}{R}= \frac{12.8 m}{0.34 m}=37.65 rad[/tex]

And that would be the angular displacement during the period of acceleration.