V$($t$)=$ Vm sin $($t $+$p$/9)$

$$ I$($t$)=$Im sin $($t$-$p$/4)$

$$

Supply frequency is $60$ Hz$.$

a$)$ Calculate the angular speed $.$ What is the unit here?

b$)$ Draw these waveforms against time.

c$)$ What is the period of these waveforms?

d$)$ Taking voltage as reference is current leading or lagging? Explain how you decide.