Answer:
a) I = 13.04 A
b) R = 8.82 ohms
c) 1291.87 kilocalories are generated an hour.
Explanation:
let P be the power of the heater, V be the voltage of the heater, I be the current of the heater, R be the resistance.
a) we know that:
P = I×V
I = P/V
= (1500)/(115)
= 13.04 A
Therefore, the current of the heater is 13.04 A
b) we now have voltage and current, according to Ohm's law:
R = V/I
= (115)/(13.04)
= 8.82 ohms
Therefore, the resistance of the heating coil is 8.82 ohms.
c) the number of kilocalories generated in one hour by the heater is just the energy the heater produces in one hour which is given by:
E = P×t
= (1500)(1×60×60)
= 5400000 J
since 1 calorie = 4.81 J
1 kilocalorie = 0.001 calories
E = 5400000/4.18 ≈ 1291866.029 calories ≈1291.87 kilocalories
Therefore, 1291.87 kilocalories are produced/generated in one hour.
Ozone in the upper atmosphere has been depleted by
B. chlorofluorocarbons
Answer: Friction is an important thing in life and we use it to move things or friction is used on us.
Explanation: Friction happens when you rub against something or when someone or something rubs against you.
To solve this problem we will apply the concepts related to the Doppler effect. According to this concept, it is understood as the increase or decrease of the frequency of a sound wave when the source that produces it and the person who captures it move away from each other or approach each other. Mathematically this can be described as
Here,
= Original frequency
= Velocity of the observer
= Velocity of the speed
Our values are,
Using the previous equation,
Rearrange to find the velocity of the observer
Replacing we have that
Therefore the velocity of the observer is 16.2m/s
I'm pretty sure that the only right answer is <span>B) a north-seeking pole of unit strength with a south-seeking pole of the same strength. Because there are no single magnetic poles.</span>