The angular velocity of the disk is defined by ω = ( 5 t 2 + 2 ) r a d / s , where t is in seconds. Determine the magnitudes of the velocity and acceleration of point A on the disk when t = 0.5 s .

Respuesta :

Answer

given,

Assume radius of the disk be = 0.8 m

angular velocity of disk

ω = ( 5 t² + 2 ) r a d / s

magnitude of velocity and acceleration = ?

At the instant of time, t = 0.5 s

ω = ( 5 x (0.5)² + 2 ) r a d / s

ω = 3.25 r a d / s

[tex]\alpha = \dfrac{d\omega}{dt}[/tex]

[tex]\alpha = \dfrac{d}{dt}( 5 t² + 2)[/tex]

[tex]\alpha =10 t[/tex]

[tex]\alpha =10\times 0.5[/tex]

α = 5 rad/s²

velocity

v = ω r

v = 3.25 x 0.8

v = 2.6 m/s

tangential acceleration

[tex]a_t = \alpha r[/tex]

[tex]a_t =5 \times 0.8[/tex]

[tex]a_t =4\ m/s^2[/tex]

normal acceleration

[tex]a_n = \omega^2\ r[/tex]

[tex]a_n = 3.25^2\times 0.8[/tex]

[tex]a_n =8.45 \m/s^2[/tex]

[tex]a = \sqrt{a_n^2 + a_t^2}[/tex]

magnitude of the acceleration

[tex]a = \sqrt{8.45^2 + 4^2}[/tex]

a = 9.35 m/s²