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}\\ time=\frac{work.done}{power}\\ =\frac{720J}{90W} \\=8 seconds[/tex]
