Answer:
8 seconds
Explanation:
power (P) is defined as the rate at which work is done.
power is measured in Watts (W) , when the work done is measured in Joules (J) and time in seconds
by the definition of power,
[tex]Power=\frac{work.done}{time.taken} \\ \\ time.taken=\frac{work.done}{power}\\=\frac{720J }{90W} \\ \\ =8 s[/tex]
