Answer:
a is 750 second
b is 2 hour
The time it takes for the train to travel 30,000m and 50,000m is 750seconds and 1250 seconds, respectively.
What is speed?The speed is the distance covered by an object at a particular time. Therefore, it is the ratio of distance and time.
[tex]\rm{Speed = \dfrac{Distance}{Time}[/tex]
A train travels at 40m/s. Now, the time it takes to travel the given distance is,
A.) 30,000m
Speed = Distance / Time
Time = Distance / Speed
Time = 30,000m / 40m/s
Time = 750 seconds
B.) 50 km
1 km = 1000m
50 km = 50 × 1000m = 50,000 m
Speed = Distance / Time
Time = Distance / Speed
Time = 50,000m / 40m/s
Time = 1250 seconds
Hence, the time it takes for the train to travel 30,000m and 50,000m is 750seconds and 1250 seconds, respectively.
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A runner of mass 80 kg is moving at 8.0 m/s. Calculate her kinetic energy.
Answer:
2560J
Explanation:
By definition the kinetic energy can be calculated in the following way:
K = (mv²)/2 = 80kg·(8.0m/s)²/2 = 2560 J
Why is visual constancy important?
A.
It gives people the ability to see things both close up and far away.
B.
It lets people of all ages see the edges of cliffs so they don’t fall over.
C.
It allows perceptions to remain the same even as images change.
D.
It offers the chance to use one retina at a time to interpret an image.
Reset
Answer:
C.
Explanation:
Visual constancy is a key mechanism that allows the perception to remain.the same even as images change
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Visual constancy is important because it allows perceptions to remain the same even as images change.
What is Constancy phenomenon?Constancy phenomenon describes how people and animals tend to perceive familiar objects as having a constant shape, size, colour, or location regardless of adjustments to distance, illumination, or perspective. Instead of responding to the real stimulus, the impression has a tendency to adapt to the object as it is or is imagined to be.
The ability to recognise things in a variety of situations, which appear to be "taken into account" throughout a process of mental rebuilding of the known image, is a result of perceptual constancy. For instance, snow appears white in both the dim moonlight and the 800,000-fold brighter day. Reduced contextual cues that help with object identification and limited experience with the object both affect perceptual constancy.
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A 3.1 kg ball is dropped from the top of a 38 m tall building. What is the speed of the ball when it is halfway from the building to the ground? Round your answer to 2 decimal places.
Answer:
19.3m/s
Explanation:
Use third equation of motion
[tex]v^2-u^2=2gh[/tex]
where v is the velocity at halfway, u is the initial velocity, g is gravity (9.81m/s^2) and h is the height at which you'd want to find the velocity
insert values to get answer
[tex]v^2-0^2=2(9.81m/s^2)(38/2)\\v^2=9.81m/s^2 *38\\v^2=372.78\\v=\sqrt[]{372.78} \\v=19.3m/s[/tex]
using dimensional analysis find the relation between the velocities of transverse waves produced from the vibration of thin homogeneous string and between the tension in the string and mass per unit length of it.
Answer:
[tex]v^2=\frac{T}{M}[/tex]
where v = transverse wave velocity, T = tension in the string, M = mass per unit length.
Explanation:
Dimensional analysis is where you just look at the units and see how they fit within each other.
In this case, all relationships are made using the MLT comparisons, where M stands for Mass, L stands for Length, and T stands for time.
For example, for velocity, we know the SI unit for velocity is [ms⁻¹] which is L¹T⁻¹, we can do the same thing for tension = [N = Kgms⁻²] = M¹L¹S⁻², and for the mass per unit length which we can think of as [Kgm⁻¹] = M¹L⁻¹.
If you play around a little with the powers, you can find a relationship:
[tex]v^2=\frac{T}{M}[/tex]
since:
[L¹T⁻¹]² = L²T⁻² = M¹L¹T⁻² ÷ M¹L⁻¹ = M¹⁻¹L¹⁻⁽⁻¹⁾T⁻² = M⁰L²T⁻² = L²T⁻²
A metal bar has a volume of 32 cm3. The mass of the bar is 256 g. What is the density of the metal? A. 290 g/cm3 6 B. 8,200 g/cm C. 8.0 g/cm3 O D. 220 g/cm
The density of the metal is ρ = 8.0g/cm³.
Why is density important?The measure of material how densely it is packed together is called density. As the mass per unit volume, it has that definition. Symbol for density: D or Formula for Density: When is the density, m is the object's mass, and V is its volume, the equation is: = m/V.
Because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. As long as an object's density is lower than the liquid's density, it will often float.
Equation :To the given equation we have :
mass of the bar = 256g
volume of metal bar = 32cm³
So according to the formula of density
ρ = m/V
So, putting values
ρ = 256g /32cm³
ρ = 8.0g/cm³
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Two moles of an ideal monatomic gas go through the cycle abc. For the complete cycle, 800 J of heat flows out of the gas. Process ab is at constant pressure, and process bc is at constant volume. States a and b have temperatures Ta = 200 K and Tb = 300 K.
(a) Sketch the all possible pV-diagrarns for the cycle.
(b) What is the work W for the process ca?
a) Sketches of all possible pv-diagrams for the cycle are attached below
b) The work W[tex]_{ac}[/tex] for the process Ca is : 2462.8 J
Given data :
Amount of heat flowing out = 800 J
Ta = 200 K
Tb = 300 K
R = 800
B) Determine the work W for the process Ca
Wₐs = -pdv
= - [ pVb - pVa ] ---- ( 1 )
note : pVb = nRTb , pVa = nRTa
Equation ( 1 ) becomes
= -nR [ Tb - Ta ]
= - 2(8.314 ) [ 300 - 200 ]
= - 1662.87
given that W[tex]_{bs}[/tex] = 0 which is isochonic
dv = 0 ( cyclic process ) = d∅ - dw
∴ 0 = 800 - ( Wₐs + W[tex]_{ac}[/tex] )
Therefore : W[tex]_{ac}[/tex] = 800 + 1662.8 = 2462.8 J
Hence we can conclude that the work W for the process Ca = 2462.8 J
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