Answer:

Explanation:
When unpolarized light passes through the first polarizer, the intensity of the light is reduced by a factor 1/2, so
(1)
where I_0 is the intensity of the initial unpolarized light, while I_1 is the intensity of the polarized light coming out from the first filter. Light that comes out from the first polarizer is also polarized, in the same direction as the axis of the first polarizer.
When the (now polarized) light hits the second polarizer, whose axis of polarization is rotated by an angle
with respect to the first one, the intensity of the light coming out is
(2)
If we combine (1) and (2) together,
(3)
We want the final intensity to be 1/10 the initial intensity, so

So we can rewrite (3) as

From which we find



Velocity is displacement/time
(Displacement is the overall change in distance)
So you’ll want to divide 200 by 25, which should give you:
8 m/s
Answer:
K = 588.3 N/m
Explanation:
From a forces diagram, and knowing that for the maximum value of K, the crate will try to rebound back up (Friction force will point downward):
Fe - Ff - W*sin(22) = 0 Replacing Fe = K*X and then solving for X:

By conservation of energy:

Replacing our previous value for X and solving the equation for K, we get maximum value to prevent the crate from rebound:
K = 588.3 N/m
Answer:
630 Hz.
Explanation:
As we are considering the one end open pipe. So for the sound wave there will be a pressure node at the open end of the tube as at that place the molecules can not move back and forth. However on the closed end there will be a flow node as the water molecules their are moving back and forth. So it will produces the resonance at the positions 1/4, 3/4.......
we can find the wavelength by multiplying the levels distance by 2.
λ = 2 × 0.27 m = 0.54
f = Vs/λ
= 340/0.54
= 630 Hz
mass of two students are


distance between them is given as

now gravitational force between them is given as

now plug in all values


so above is the force of gravitation between them