Complete question is;
In searching the bottom of a pool at night, a watchman shines a narrow beam of light from his flashlight 125 cm above the water level to a point 185 cm from his foot at the edge of the pool. Where does the spot of light hit the bottom of the pool, relative to the edge, if the pool is 215 cm deep
Answer:
356.2 cm
Explanation:
First of all, let's find the angle of incidence from the distances
;
tan θ1 = l1/h1
tan θ1 = 185/125
tan θ1 = 1.48
θ1 = tan^(-1) 1.48
θ1 = 55.95°
For the refraction from air into water, we have
n_air × sin θ1 = n_water × sin θ2,
sin θ2 = (n_air × sin θ1)/n_water
Where,
n_water is refractive index of water = 1.33
n_air is refractive index of air = 1
Thus;
sin θ2 = (1 × sin 55.95)/1.33
sin θ2 = 0.62297
θ2 = sin^(-1) 0.62297
θ2 = 38.53°
So, the horizontal distance from the edge of the pool from
l is;
l = l1 + l2 = l1 + h2 tan θ2
where;
l1 = 185cm
h2 = 215 cm
So,
l = 185 + 215(tan 38.53)
l = 185 + 171.2045
l = 356.2045 cm ≈ 356.2 cm
Explanation:
Pressure of a liquid :
Liquids also exert pressure as that in case of solids. We can understand it as the fact that it is impossible to hammer a nail with liquid. That's why liquid exert pressure on its surface. The formula for the pressure in liquid is given by :
Where
= density of liquid
g = acceleration due to gravity
h = height
The SI init of pressure is Pascal and it is dented by Pa.
Explanation:
(b) A uniform beam 150cm long weighs 3.5kg and
supported on knife-edges at its ends. The beam
supports a weight 7kg at a distance 30cm from
one end. Find the reactions of the supports.
Answer:
a) 0.09N b) positive x direction
Explanation:
Force on a conductor carrying current in a magnetic field can be expressed as;
F = BILsin(theta) where
F is the force on the conductor (wire)
B is the uniform magnetic field I'm Tesla = 1.8Tesla
I is the current in the wire = 5×10^-2A
L is the length of the wire = 1m
theta is the angle that the conductor make with the magnetic field = 90° (since the wire in the horizontal direction is perpendicular to the field acting upwards)
Substituting this value in the formula to get F we have;
F = 1.8×5×10^-2×1 × sin90°
F = 0.09N
The force on the wire is 0.09N
b) The direction of the force is in the positive x direction since the wire acts horizontally to the magnetic field.
a) time, t = 11.407 s, b) distance x = 175.66 m, v = c) speed v = 30.80 m / s
<h3>Explanation of question:</h3>
a) This is kinematics exercise, write the equation of each vehicle car is;-
x = x₀ + v₀ t + ½ a t²
Let's fix our the reference system at a point where the car indicate that the car stops from rest is vo = 0.
x₀ = v₀ = 0
<h3>we substitute</h3>
x = ½ a t²
truck
x₂= v₀ t
v₀ = 15.4 m / s
At the point where they are, positions are equal:-
½ a t² = vo t
t = 2 vo / a
calculate us
t = 2 15.4 / 2.
t = 11.407 s
b) the distance to reach it
x = ½ to t²
x = ½ 20 11.407²
x = 175.66 m
c) the speed of the car is
v = vo + a t
vo = 0
v = at
v = 2.0 11.407
v = 30.80 m / s
To know more about acceleration visit:-
brainly.com/question/12550364
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