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
Answer:
The acceleration of the cart is 1.0 m\s^2 in the negative direction.
Explanation:
Using the equation of motion:
Vf^2 = Vi^2 + 2*a*x
2*a*x = Vf^2 - Vi^2
a = (Vf^2 - Vi^2)/ 2*x
Where Vf is the final velocity of the cart, Vi is the initial velocity of the cart, a the acceleration of the cart and x the displacement of the cart.
Let x = Xf -Xi
Where Xf is the final position of the cart and Xi the initial position of the cart.
x = 12.5 - 0
x = 12.5
The cart comes to a stop before changing direction
Vf = 0 m/s
a = (0^2 - 5^2)/ 2*12.5
a = - 1 m/s^2
The cart is decelerating
Therefore the acceleration of the cart is 1.0 m\s^2 in the negative direction.
Answer: because increasing biodiversity can influence ecosystem functions such as productivity and variety and even the likelihood that a particular species is discovered by a comminity
Explanation:
Answer:
speed is equal to distance/time
so 2m/40s
=0.05
Answer:
0.04455 Hz
Explanation:
Parameters given:
Wavelength, λ = 6.5km = 6500m
Distance travelled by the wave, x = 8830km = 8830000m
Time taken, t = 8.47hours = 8.47 * 3600 = 30492 secs
First, we find the speed of the wave:
Speed, v = distance/time = x/t
v = 8830000/30492 = 289.58 m/s
Frequency, f, is given as velocity divided by wavelength:
f = v/λ
f = 289.58/6500
f = 0.04455 Hz