Answer:
1. 1800 W
2. $ 17.3
Explanation:
From the question given above, the following data were obtained:
Current (I) = 15 A
Voltage (V) = 120 V
Time (t) = 20 h per day
Duration = 31 days
Cost = 15.5 cents per kWh
1. Determination of the power.
Current (I) = 15 A
Voltage (V) = 120 V
Power (P) =?
P = IV
P = 15 × 120
P = 1800 W
Thus, 1800 W of power is required.
2. Determination of the cost per month (31 days).
We'll begin by converting 1800 W to KW.
1000 W = 1 KW
Therefore,
1800 W = 1800 W × 1 KW / 1000 W
1800 W = 1.8 KW
Next, we shall determine the energy consumption for 31 days. This can be obtained as follow:
Power (P) = 1.8 KW
Time (t) = 2 h per day
Time (t) for 31 days = 2 × 31 = 62 h
Energy (E) =?
E = Pt
E = 1.8 × 62
E = 111.6 KWh
Finally, we shall determine the cost of consumption. This can be obtained as follow:
1 KWh = 15.5 cents
Therefore,
111.6 KWh = 111.6 KWh × 15.5 cents / 1 KWh
111.6 KWh = 1729.8 cents
Converting 1729.8 cents to dollar, we have:
100 cents = $ 1
Therefore,
1729.8 cents = 1729.8 cents × $ 1 / 100 cents
1729.8 cents = $ 17.3
Thus, it will cost $ 17.3 per month to run the electric heater.
Answer:
678.2 km/h and 80.54° north of east
Explanation:
From the question,
Using pythagoras theorem,
a² = b²+c²..................... Equation 1
Where a = resultant velocity
Given: b = 600 km/h, c = 100 km/h
Substitute these values into equation 1
R² = 600²+100²
R² = 360000+10000
R² = 460000
R = √460000
R = 678.2 km/h.
And the direction is
tanθ = 600/100
tanθ = 6
tanθ = 6
θ = tan⁻¹(6)
θ = 80.54°.
Hence the resultant velocity of the aircraft is 678.2 km/h and 80.54° north of east
First:
d = 100 m
t = 200 sec
v = 100/200 = 0.5 m/s
Displacement is zero since he returned to his start point.
t2 = d/v2 = 100/2 = 50 sec
total time = 50 + 200 + 500 = 750 sec
Popcorn can be popped by either of the three forms of heat transfer:
Conduction in a pan with hot oil on a stove element.
Convection by an air popper and warm air rising over a heating element... no direct contact with heat source.
Radiation is what occurs in a microwave. Invisible radiant heat activates water molecules in the popcorn.
All the above heat the kernel over 100 Celsius. Water vaporizes/boils (latent heat) and erupts through the kernel.
Mmmm popcorn watch out for the lipids (fat in the oil and butter)