Answer:
Intensity of beam 18 feet below the surface is about 0.02%
Explanation:
Using Lambert's law
Let dI / dt = kI, where k is a proportionality constant, I is intensity of incident light and t is thickness of the medium
then dI / I = kdt
taking log,
ln(I) = kt + ln C
I = Ce^kt
t=0=>I=I(0)=>C=I(0)
I = I(0)e^kt
t=3 & I=0.25I(0)=>0.25=e^3k
k = ln(0.25)/3
k = -1.386/3
k = -0.4621
I = I(0)e^(-0.4621t)
I(18) = I(0)e^(-0.4621*18)
I(18) = 0.00024413I(0)
Intensity of beam 18 feet below the surface is about 0.2%
To calculate that, we'd need to know the coefficient of static friction between the block and the surface, which you haven't told us.
Answer:
Inward
Explanation:
As the centripetal force acts upon an object moving in a circle at constant speed, the force always acts inward as the velocity of the object is directed tangent to the circle. This would mean that the force is always directed perpendicular to the direction that the object is being displaced. hope this helps :)
Answer:
There are seven fundamental physical quantities they are: length, mass, time, electric current, temperature, amount of substance, and light intensity.
Answer:
Explanation:
h = height of the cliff
Consider upward direction as positive and downward direction as negative
Consider the motion of rock thrown straight up :
Y = vertical displacement = - h
v₀ = initial velocity = 8.63 m/s
a = acceleration = - 9.8 m/s²
t = time taken to hit the ground = 3 s
Using the equation
Y = v₀ t + (0.5) a t²
- h = (8.63) (3) + (0.5) (- 9.8) (3)²
h = 18.21 m
Consider the motion of rock thrown down :
Y' = vertical displacement = - 18.21
v'₀ = initial velocity = - 8.63 m/s
a' = acceleration = - 9.8 m/s²
t' = time taken to hit the ground = ?
Using the equation
Y' = v'₀ t' + (0.5) a' t'²
- 18.21 = (- 8.63) t' + (0.5) (- 9.8) t'²
t' = 1.2 s
