Which of the following statements are true? (Select all that apply.) Ammeters have a relatively high resistance and are placed i
1 answer:
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Answer:
a. 7.89 Ω, 1.14 W
b. By a factor of 2; The batteries would heat up.
Explanation:
a. Using Ohm's law, we have that Voltage, V, is directly proportional to Current, I, with the constant of proportionality being Resistance, R. Mathematically:
V = IR
The voltage of the two batteries would be:
V = V1 + V2 = 1.5 + 1.5 = 3.0 V
The current is 380 mA = 0.38 A
Hence, the Resistance, R, will be:
R = 7.89 Ω
Power is given as:
P = IV
P = 3 * 0.38
P = 1.14 W
b. If the batteries are now 4, the new voltage will be:
V = 4 * 1.5
V = 6 V
Power becomes:
P = 0.38 * 6
P = 2.28 W
Comparing with Power in (a) above, we see that the new Power is double the value of the former Power. Hence, the Power has increased by a factor of 2.
It is not advisable to use double the number of batteries to power a flashlight because it would cause the batteries to heat up and thereby, leak or in the worst case scenario, blow up. This could be damaging to the flashlight.
Answer
given,
time of disk stayed a loft = 16.7 sec
height reached = 18.4 m
mass = 72 kg
now work done is equal to change in potential energy
W = 12983.04 J
Positive sign means that work is in the direction of motion.
P = 777.42 Watts