Answer:
The resistance is 
Explanation:
Given that,
Diameter of tube = 8.5 mm
Length = 8 cm
Resistivity = 2.5 m
We need to calculate the resistance
The resistance is equal to the product of the resistivity and length divided by the area of cross section .
In mathematical form,
Where, 
=resistivity
l = length
A = area of cross section
Put the value into the formula
Hence, The resistance is
Answer:
it depends on wether the + and - are facing eachother
or away from eachother
Explanation:
The force required to slow the truck was -5020 N
Explanation:
First of all, we find the acceleration of the truck, which is given by
where
v is the final velocity
u is the initial velocity
t is the time
For the truck in this problem,
v = 11.5 m/s
u = 21.9 m/s
t = 2.88 s
So the acceleration is
where the negative sign means that this is a deceleration.
Now we can find the force exerted on the truck, which is given by Newton's second law:
where
m = 1390 kg is the mass of the truck
is the acceleration
And substituting,
So the closest answer among the option is -5020 N.
Learn more about acceleration and forces:
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Answer: 4.speed
Explanation:
In this case, we know that the cart remains at a constant 20km/h.
Now, one could say that "the velocity remains constant, because it always is 20km/h"
But remember that velocity is a vector, so this has a direction, and if the cart is going around a turn, then the direction of motion is changing, which tell us that there is acceleration.
But the module of the velocity, the speed, remains constant at 20km/h.
Then the correct option is 4, speed.
Answer:
The difference between the cost of operating LED and incandescent bulb is $5.1
Explanation:
We are given the cost of electricity that is 12.75 cents per kWh. We want to find out the difference in the operating cost of an incandescent and LED bulb for a time period of 2,000 hours.
Since we are not given the rating of the incandescent bulb and LED bulb, we will assume their ratings.
For a light intensity of 250 Lumens;
The average rating of an LED bulb is approximately 5 Watts.
The average rating of an incandescent bulb is approximately 25 Watts.
Now lets find out the kWh of each bulb.
Energy = Power×Time
For LED bulb:
E = 5×2,000 = 10,000 Wh
Divide by 1000 to convert into kWh
E = 10,000/1000 = 10 kWh
Cost = 12.75×10 = 127.5 cents
Cost = $1.27
For Incandescent bulb:
E = 25×2,000 = 50,000 Wh
Divide by 1000 to convert into kWh
E = 50,000/1000 = 50 kWh
Cost = 12.75×50 = 637.5 cents
Cost = $6.37
Difference in Cost:
Difference = $6.37 - $1.27 = $5.1
Therefore, the difference between the cost of operating LED and incandescent bulb is $5.1.
