Answer:
a. 5 batteries b. 1050 mAh
Explanation:
Here is the complete question
A student project is required to be portable and hand held. It requires 6 V DC power at a current of 150 mA. The batteries for the power supply must last for a minimum of 7 hours of continuous operation. NiMH rechargeable batteries in AA size are to be used. A) How many batteries are needed? B) What mAh capacity should the batteries have?
Solution
A) How many batteries are needed?
Since the nominal voltage for a single NiMH battery is 1.2 V per battery and we require 6V DC power, we combine the batteries in series to obtain a total voltage of 6 V. The number of batteries required, n = total voltage/voltage per cell = 6V/1.2V per battery = 5 batteries
So, the number of batteries needed is 5.
B) What mAh capacity should the batteries have?
Since the batteries are in series, they would each deliver a current of 150 mA. Since we require a current of 150 mA for 7 hours, the number of milliampere-hours capacity mAh of batteries required is Q = It where I = current = 150 mA and t = time = 7 hours.
So, Q = It = 150 mA × 7 h = 1050 mAh.
So, the batteries should have a mAh of 1050 mAh
The Avogadro’s number is used to represent the number of elementary entities that exist in one mole of a compound.
<h3>What is the Avogadro’s number?</h3>
The Avogadro’s number is used to represent the number of elementary entities that exist in one mole of a compound. The numerical value of the Avogadro’s number is obtained as 6.02 x 10^23 and consists of the atoms, molecules and ions in the compound.
The scientist Josef Loschmidt strengthened the Avogadro’s number by obtaining the number of particles in one cubic centimeter of gas under standard conditions.
Learn more about Avogadro's number:brainly.com/question/11907018
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The correct answer is:
That the land where it specifically was has been moving and that years ago that place was under water.
Explanation:
Kansas has been the cause of some of the most luxurious fossil findings in US history. The fossil record of Kansas spans from the Cambrian to the Pleistocene. From the Cambrian to the Devonian, Kansas was coated by a shallow sea.
Answer:
Value of angle between vector a and b is 
.
Explanation:
Vectors a and b have scalar product 6.00
Let 
be the angle between a and b.
ab cos = 6 ...(1)
Vectors a and b have magnitude of vector product 9.00
ab sin = 9 ...(2)
Dividing equation (2) by (1) we get
tan = 1.5
=
Thus, value of angle between vector a and b is .
Assuming g = 10, the weight of the sled is 720N.
If it takes 26.5N to just pull the sled, then the frictional force f is 26.5N in the opposite direction.
f = μ*720N
26.5N = μ*720N
μ = 26.5N/720N = 0.037 (2 s.f.)
