Question

Your washer has a power of 350 watts and your dryer has a power of 1800 watts how much energy do you use to clean a load of clothes in 1 hour of washing and 1 hour of drying?

A. 1.29 x 10^3 J
B. 2.58 x 10^3 J
C. 1.55 x 10^7 J
D. 7.74 x 10^6 J

Answer 1

7.74 x 10⁶ Joules

Step-by-step explanation:

recall that "Watts" is the SI unit used for "energy per unit time"

Hence "Watts" may also be expressed as Joules / Second (or J/s)

We are given that the washer is rated at 350W (i.e. 350 Joules / s) and the dryer is rated at 1800W (i.e. 1800 Joules / s).

We are also given that the appliances are each run for 1 hour

1 hour = 60 min = (60 x 60) seconds = 3600 seconds

Hence the total energy used,

= Energy used by Washer in 1 hour + Energy used by dryer in 1 hour

= (350 J/s x 3600 s) + (1800 J/s x 3600 s)

= 3600 ( 350 + 1800)

= 3600 (2150)

= 7,740,000 Joules

= 7.74 x 10⁶ Joules