A cord is wound around the circumference of a bicycle wheel (without tyre) of diameter `1 m`. A mass of `2 kg` is tied at the end of the cord and it is allowed to fall from rest. The weight falls `2 m` in `4 s`. The axle of the wheel is horizontal and the wheel rotates which its plane vertical. if `g = 10 ms^(-2)`, what is the angular acceleration of the wheel ?

Explanation

Here, `r = (1)/(2)m = 0.5m,m = 2 kg`
`s = 2m, t = 4s, g = 10ms^(-2), alpha = ?`
As `s = u t + (1)/(2) at^(2)`
`:. 2 = 0 + (1)/(2) a(4)^(2) , a= (1)/(4) m//s^(2)`
As `a = r alpha :. alpha = (a)/(r ) = (1//4)/(0.5) = 0.5 rad//s^(2)`