Question

Your washer has power of 450 watts, and your dryer has a power of 3000watts. How much energy do you use to clean a load of clothes in 1 hour ofwashing and 1.5 hours of drying?OA. 3.11 x 107 JOB. 1.78 x 107 JOC. 5.17 x 10³ JOD. 2.97 x 10³ J

Answer 1

B. 1.78 x 10⁷ J

Step-by-step explanation

Given:

• The power of the washer, P₁ = 450 W

,

• The power of the dryer, P₂ = 3000 W

,

• The time needed to wash one load of clothes, t₁ = 1 hour

,

• The time needed to dry those clothes, t₂ = 1.5 hours

Energy is the product of power and time,

`E=P\cdot t`

If the power is given in watts, we have to convert the time to seconds, so that the energy is in Joules. Knowing that 1 hour has 3600 seconds,

`\begin{gathered} t_1=1hour\cdot(3600s)/(1hour)=3600s \\ \\ t_2=1.5hour\cdot(3600s)/(1hour)=5400s \end{gathered}`

So the energy needed to wash the clothes is,

`E_1=P_1\cdot t_1=450W\cdot3600s=1.62\cdot10^6J`

And the energy needed to dry them,

`E_2=P_2\cdot t_2=3000W\cdot5400s=16.2\cdot10^6J`

So, the total energy needed for the whole cycle is,

`E=E_1+E_2=1.62\cdot10^6J+16.2\cdot10^6J=(1.62+16.2)\cdot10^6J=17.82\cdot10^6J=1.78\cdot10^7J`

Hence, the energy needed to wash the clothes for 1 hour and dry them for 1.5 hours is 1.78 x 10⁷ J.