An electric drill starts from rest and rotates with a constant angular acceleration. After the drill has rotated through a certain angle, the magnitude of the centripetal acceleration of a point on the drill is twice the magnitude of the tangential acceleration. What is the angle?

Respuesta :

Answer:

Explanation:

Given

magnitude of centripetal acceleration is twice the magnitude of tangential acceleration

Suppose [tex]\theta [/tex] is theta angle rotated by electric drill

it is given that it starts from rest i.e. [tex]\omega _0=0[/tex]

suppose [tex]\omega [/tex] and [tex]\alpha [/tex] is the final angular velocity and angular acceleration

using rotational motion equation

[tex]\omega ^2-\omega _0^2=2\times \alpha \times \theta [/tex]

where [tex]\theta [/tex]=angle turned by drill

[tex]\omega _0[/tex]=initial angular velocity

[tex]\omega [/tex]=final angular velocity

[tex]\alpha [/tex]=angular acceleration

[tex]\omega ^2-0=2\times \alpha \times \theta [/tex]

[tex]\omega ^2=2\alpha \theta ---1[/tex]

It is also given that centripetal acceleration is twice the magnitude of tangential i.e.

[tex]\omega ^2r=\alpha \times r[/tex]

where r=radial distance of any point from axis of drill

i.e. [tex]\omega ^2=\alpha [/tex]

substitute this value to equation 1

we get

[tex]\theta =\frac{\omega ^2}{2\alpha }[/tex]

[tex]\theta =1\ rad[/tex]