Answer:
The lenses with different focal length are four.
Explanation:
Given that,
Radius of curvature R₁= 4
Radius of curvature R₂ = 8
We know ,
Refractive index of glass = 1.6
When, R₁= 4, R₂ = 8
We need to calculate the focal length of the lens
Using formula of focal length

Put the value into the formula



When , R₁= -4, R₂ = 8
Put the value into the formula



When , R₁= 4, R₂ = -8
Put the value into the formula



When , R₁= -4, R₂ = -8
Put the value into the formula



Hence, The lenses with different focal length are four.
Answer:
it will take 36.12 ms to reduce the capacitor's charge to 10 μC
Explanation:
Qi= C×V
then:
Vi = Q/C = 30μ/20μ = 1.5 volts
and:
Vf = Q/C = 10μ/20μ = 0.5 volts
then:
v = v₀e^(–t/τ)
v₀ is the initial voltage on the cap
v is the voltage after time t
R is resistance in ohms,
C is capacitance in farads
t is time in seconds
RC = τ = time constant
τ = 20µ x 1.5k = 30 ms
v = v₀e^(t/τ)
0.5 = 1.5e^(t/30ms)
e^(t/30ms) = 10/3
t/30ms = 1.20397
t = (30ms)(1.20397) = 36.12 ms
Therefore, it will take 36.12 ms to reduce the capacitor's charge to 10 μC.
The astronaut will take 300 seconds
Explanation:
We can solve this problem by using the law of conservation of momentum.
In fact, the total momentum of the astronaut+object system must be conserved.
Initially, they are both at rest, so their total momentum is zero:

After the astronaut throws the object, their total momentum is:

where:
M = 80 kg is the mass of the astronaut
V is the final velocity of the astronaut
m = 500 g = 0.5 kg is the mass of the object
v = 8.0 m/s is the velocity of the object
Since momentum is conserved, we can write

And solving for V,

Which means that he starts moving at 0.05 m/s in the direction opposite to the object.
Now the astronaut needs to cover a distance of
d = 15.0 m
And his speed is
v = 0.05 m/s
Therefore, the time taken is

Learn more about momentum here:
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Answer:
Abiotic
Explanation:
The non living factors of the ecosystem which is essential for the survival of living factors of the ecosystem are abiotic factors.
Examples for abiotic factors include temperature, sunlight, water, wind etc....
Because they are not supported by the results of any legitimate investigation
that's conducted in accordance with the Scientific Method.
You may say:
"Well then, teach both lines of reasoning,
and let each student decide for himself."
This is suggested by the same people who aren't ready to let their
fourth-grader choose his own clothing, dinner menu, or school.
And it sounds reasonable to a vast mass of citizens who have decided
for them selves that the jury is still out on climate change.
What I'm saying is this:
-- The Scientific Method is a METHOD of investigation that's designed
and developed to remove the effects of human prejudice from the
collection and evaluation of evidence, and to be able to tell bogus
conclusions apart from true ones. It's the most reliable way we have
of asking and answering questions about the natural world.
-- Some questions CAN'T be studied with the Scientific Method,
because experiments generally can't be constructed. These include
matters of religion and faith. Nobody can flatly state that those are
right or wrong. We have no reliable way to say, either way.
The only way to decide is . . . faith.
-- It is illegitimate to take the answer to a question of faith that can't be
derived scientifically, and a scientifically derived conclusion, set them
down next to each other on the same table, and pretend that they can be
compared.
-- When you put them next to each other, say that they're equivalent,
and tell people "go ahead and choose one or the other", the situation
is bogus, the comparison is dishonest, and people who are untrained
or uneducated or immature are not qualified to "choose".
That's why.
This is my opinion. I could be wrong.
Personally, I happen to be a believer. But I cannot prove anything I believe
to anyone else ... not with rational argument, and not with evidence. Those are
elements of the scientific method. They're not applicable, and they don't work,
in matters of faith.