b. A girder is lowered by a crane. It is slowing down.
c. You're straining to hold a 200 lb barbell over your head.
d. A jet plane has reached its cruising speed and altitude.
e. A rock is falling into the Grand Canyon.
f. A box in the back of a truck doesn't slide as the truck stops.
Answer:
a) dynamic equilibrium; b) No equilibrium; c) Static equilibrium; d) Dynamic equilibrium; e) Not equilibrium; f) Dynamic equilibrium.
Explanation:
a) In this case, the girder is in dynamic equilibrium, although there is movement it is realized at constant speed therefore there is no acceleration and the sum of forces is equal to zero.
b) There is no equilibrium since the velocity is decreasing it slows the girder, therefore the sum of forces will be equal to the product of mass by acceleration according to newton's second law.
c) In this case, the arms of the person are exercising each 100 lb, in order to keep the barbell stable, this allows the static equilibrium.
d) There is movement but however the jet will move at constant speed without any kind of acceleration, therefore it has a condition of dynamic equilibrium.
e) There is no balance as the rock falls and the acceleration due to gravity causes its speed to increase as it goes down.
f) In this case there is dynamic equilibrium as there was a deceleration movement however this force value given by the deceleration multiplied by the mass is not large enough to be able to move the box, due to the weight of the box plus the friction force between the box and the surface.
Answer:
L' = 555.95 lb
Explanation:
Analyzing the given conditions in the question, we get
The safe load, L is directly proportional to width (w) and square of depth (d²)
also,
L is inversely proportional length (l) i.e L = k/l
combining the above conditions, we get an equation as:
L = k(wd²/l)
now, for the first case we have been given
w = 3 in
d = 6 in
l = 11 ft
L = 1213 lbs
thus,
1213 lb = k ((3 × 6²)/11)
or
k = 123.54 lbs/(ft.in³)
Now,
Using the calculated value of k to calculate the value of L in the second case
in the second case, we have
w = 6 in
d =3 in
l = 12 ft
Final Safe load L' = 123.54 × (6 × 3²/12)
or
L' = 555.95 lb
The load that a beam of the given dimensions can support is derived using a joint variation formula. The constant of variaiton is found using the given beam's characteristics, and then applied on the second beam's measurements to find its load. The result is approximately 2025 pounds.
The question is related to joint variation and its principles in mathematics. First, it's necessary to define the equation of the joint variation:
L = k*(w*d^2)/l
where L is the load, w is the width, d is the depth, l is the length, and k is the constant of proportionality. From the information given in the question, we can derive that k equals to 1213 * 11 / (3 * 6^2), which is approximately 135. Then, we substitue the values of the second beam into the equation, w = 6, d = 3, l = 12 and k = 135, to get the load L for the second beam, which equates to about 2025 pounds.
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on a boundary with corn oil. What is the angle of refraction, to the nearest degree, for this
light ray in the corn oil?
The angle of refraction of light ray in the corn oil is 20°.
Angle of refraction is the angle the refracted light ray makes with the normal to the oil-air interface.
Given data:
Angle of incidence = 30°
Analysis:
The refractive index of oil is 1.47.
Using the formula for refractive index(n) =
1.47 =
1.47(sin r) = sin 30
sin r =
sin r = 0.3401
r = arc sin(0.3401)
r = 19.88° which is approximately 20°
Learn more about Refraction : brainly.com/question/10729741
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Answer:
its 20 degrese
Explanation: