Question

The Eyebrow Trimmer 5000 XL that Duncan's "friends" used in themalicious eyebrow-shavingattack works at 30 J/s and gaveout a total of 450J of pure trimming energy.How long did it take for Duncan's friends to shave off his eyebrows?

Answer 1

In order to determine the time, use the following formula for the power:

$P=\frac{E}{t}$

where,

P = 30J/s

E = 450J

t = ?

Solve the equation above for t and simplify:

$t=\frac{E}{P}=\frac{450J}{30\frac{J}{s}}=15s$

Hence, the time was 15s