Difference in energy between the exicted states and ground states
Answer:
E. Some charges in the region are positive, and some are negative.
Explanation:
Electric potential is given as;
where;
W is the work done in moving a charge between two points which have a difference in potential
Q is quantity of charge in the given region
If the electric potential at a given point in the region is zero, then sum of the charges in the given region must be equal to zero. For the charges to sum to zero, some will be positive while some will be negative,.
Therefore, the correct statement in the given options is "E"
E. Some charges in the region are positive, and some are negative.
I'll bite:
-- Since the sled's mass is 'm', its weight is 'mg'.
-- Since the coefficient of kinetic friction is μk, the force acting opposite to the direction it's sliding is (μk) times (mg) .
-- If the pulling force is constant 'F', then the horizontal forces on the sled
are 'F' forward and (μk · mg) backwards.
-- The net force on the sled is (F - μk·mg).
(I regret the visual appearance that's beginning to emerge,
but let's forge onward.)
-- The sled's horizontal acceleration is (net force) / (mass) = (F - μk·mg) / m.
This could be simplified, but let's not just yet.
-- Starting from rest, the sled moves a distance 's' during time 't'.
We know that s = 1/2 a t² , and we know what 'a' is. So we can write
s = (1/2 t²) (F - μk·mg) / m .
Now we have the distance, and the constant force.
The total work is (Force x distance), and the power is (Work / time).
Let's put it together and see how ugly it becomes. Maybe THEN
it can be simplified.
Work = (Force x distance) = F x (1/2 t²) (F - μk·mg) / m
Power = (Work / time) = <em>F (t/2) (F - μk·mg) / m </em>
Unless I can come up with something a lot simpler, that's the answer.
To simplify and beautify, make the partial fractions out of the
2nd parentheses:
<em> F (t/2) (F/m - μk·m)</em>
I think that's about as far as you can go. I tried some other presentations,
and didn't find anything that's much simpler.
Five points,ehhh ?
The difference in weight is due to the
displacement of water (the buoyancy of water is acting on the athlete thus
giving her smaller weight).<span>
The amount of weight displaced or the amount of buoyant force
is: </span>
Fb = 690 N - 48 N
Fb = 642 N
From newtons law, F = m*g. Using this formula, we
can calculate for the mass of water displaced:
m of water displaced = 642N / 9.8m/s^2
m of water displaced = 65.5 kg
Assuming a water density of 1 kg/L, and using the
formula volume = mass/density:
V of water displaced = 65.5kg / 1kg/L = 65.5 L
The volume of water displaced is equal to the
volume of athlete. Therefore:
V of athlete = 65.5 L
The mass of athlete can also be calculated using,
F = m*g
m of athlete = 690 N/ 9.8m/s^2
m of athlete = 70.41 kg
Knowing the volume and mass of athlete, her
average density is therefore:
average density = 70.41 kg / 65.5 L
<span>average density = 1.07 kg/L = 1.07 g/mL</span>
Conservation is a method of improving air quality
