Answer:
a) λ = 189.43 10⁻⁹ m b) λ = 269.19 10⁻⁹ m
Explanation:
The diffraction network is described by the expression
d sin θ= m λ
Where m corresponds to the diffraction order
Let's use trigonometry to find the breast
tan θ = y / L
The diffraction spectrum is measured at very small angles, therefore
tan θ = sin θ / cos θ = sin θ
We replace
d y / L = m λ
Let's place in the first order m = 1
Let's look for the separation of the lines (d)
d = λ L / y
d = 501 10⁻⁹ 9.95 10⁻² / 15 10⁻²
d = 332.33 10⁻⁹ m
Now we can look for the wavelength of the other line
λ = d y / L
λ = 332.33 10⁻⁹ 8.55 10⁻²/15 10⁻²
λ = 189.43 10⁻⁹ m
Part B
The compound wavelength B
λ = 332.33 10⁻⁹ 12.15 10⁻² / 15 10⁻²
λ = 269.19 10⁻⁹ m
Since the direction of the force and the direction of the path is perpendicular, the person is not doing any physical work.
The answer is true...............
a) 2.75 s
The vertical position of the ball at time t is given by the equation

where
h = 4 m is the initial height of the ball
u = 12 m/s is the initial velocity of the ball (upward)
g = 9.8 m/s^2 is the acceleration of gravity (downward)
We can find the time t at which the ball reaches the ground by substituting y=0 into the equation:

This is a second-order equation. By solving it for t, we find:
t = -0.30 s
t = 2.75 s
The first solution is negative, so we discard it; the second solution, t = 2.75 s, is the one we are looking for.
b) -15.0 m/s (downward)
The final velocity of the ball can be calculated by using the equation:

where
u = 12 m/s is the initial (upward) velocity
g = 9.8 m/s^2 is the acceleration of gravity (downward)
t is the time
By subsisuting t = 2.75 s, we find the velocity of the ball as it reaches the ground:

And the negative sign means the direction is downward.