4)
The average value of p over a cycle is*
2
2
sin2
m
p
i R
i R
ωt
= <
> = <
>
  [7 5(a)]
where the bar over a letter (here, p) denotes its average
value and < > denotes taking average of the quantity
inside the bracket Since,  i2
m and R are constants,
2
sin2
m
p
i R
ωt
=
<
>
[7