I have the same physics class , so the answer would be 0.6
Answer:
9R
Explanation:
We know that the resistance is
.
If we stretch the wire to a new length L2 = 3L, the cross-sectional area will also change. If the cross-sectional area doesn't change throughout the wire, we can say that:
Volume = L*A = 3L * A2 being A2 the new area after stretching the wire.
Since the volume remains the same we conclude that A2 = A/3
With this information, we calculate the new resistance:

Since
, and by simple inspection of the previous equation, we get:
<em>R2 = 9*R</em>
Answer:
54 Kobo
Explanation:
Units of <u>electricity</u> are measured in kilowatt hours (kWh).
Given information:
- 900 watt electric iron
- Appliance usage = 4 hours a week for 5 weeks
- Unit cost of electricity = 3 Kobo per kWh
<h3><u>Step 1</u></h3>
Convert the wattage of the electric iron from watts to kilowatts.
1000 watts (W) = 1 kilowatt (kW)
⇒ 900 watts = 1 ÷ 1000 = 0.9 kilowatts
This means that the power consumption of the electric iron is 0.9 kW per hour of use.
<h3><u>Step 2</u></h3>
Total hours spent pressing clothes:
= 4 hours per week for 5 weeks
= 4 × 5
= 20 hours
<u>Total power consumption</u>:
= number of kW × number of hours
= 0.9 × 20
= 18 kWh
<h3><u>Step 3</u></h3>
To find the <u>total cost</u>, multiply the total kWh by the cost per kWh:
⇒ Cost = 18 × 3 = 54 Kobo
Wouldn't everything fall?