A train travels at 40m/s. Calculate the time it takes to travel:
A) 30,000 m
B) 50 km
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The density of the metal is ρ = 8.0g/cm³.

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.

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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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

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.

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) 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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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]

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