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3 years ago

10

A freight car moves along a frictionless level railroad track at constant speed. The freight car is open on the top. A large loa

d of sand is suddenly dumped into the freight car. What happens to the speed of the freight car?

1 answer:

Fittoniya [83]3 years ago

3 0

The added weight of the sand puts more downward pressure on the wheels contacting the rails, which would cause the trains speed to decrease.

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Complete the sentences below using the words below, you may use each word more than once

satela [25.4K]

Decreases, stays the same, increases. The volume decreases because as air is cooled, the individual molecules collectively possess less kinetic energy and the distances between them decrease, thus leading to a decrease in the volume they occupy at a certain pressure (please note that my answer only holds under constant pressure; air, as a gas, doesn't actually have a definite volume). The mass stays the same because physical processes do not create or destroy matter. The law of conservation of mass is obeyed. You're only cooling the air, not adding more air molecules. The density decreases because as the volume decreases and mass stays the same, you have the same mass occupying a smaller volume. Density is mass divided by volume, so as mass is held constant and volume decreases, density increases.

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3 years ago

A museum curator moves artifacts into place on various different display surfaces. If the curator moves a 145 kg aluminum sculpt

NikAS [45]

We are given the mass of an <span>aluminum sculpture which is 145 kg and a horizontal force equal to 668 Newtons. The coefficient of friction can be determined by dividing the horizontal force by the weight of the object. In this case, 668 N / 145 * 9.8 equal to coeff of friction of 0.47</span>

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3 years ago

Read 2 more answers

How to get more water pressure in shower?

tia_tia [17]

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3 years ago

a circular loop is hanging on the wall. it has a radius of 33.3 cm and is comprised of 12 coils. there is a magnetic field perpe

Vika [28.1K]

Answer:

I = 2.19A, anticlockwise direction.

Explanation:

Given r = 33cm = 0.33m, N = 12, ΔB = 7.5 - 1.5 = 6.0T, Δt = 3s, R = 3.75Ω

By Faraday's law of electromagnetic induction when there is a change in flux in a coil or loop, an emf is induced in the coil or loop which is proportional to the time rate of change of the magnetic flux through the loop.

The emf E is related to the flux by the formula

E = – NdФ/dt

Where N = number of turns in the coil, Ф = magnetic flux through the loop = BA, B = magnetic field strength, A = Area

In this problem the strength of the magnetic field changes. As a result the flux too changes and an emf is induced in the coil.

So

ΔФ = ΔB×A = ΔB×πr² = 6×π×0.33² = 2.05Wb

E = -NΔФ/Δt = 12×2.05/3 = 8.2V

I = E/R = 8.2/ 3.75 = 2.19A

The direction of the current can be found by pointing the thumb of your right hand in the direction of the magnetic field and curling the remaining fingers around this direction. The direction of the curl of these fingers give the direction of current which in this case is anticlockwise.

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3 years ago

A seismographic station receives S and P waves from an earthquake, separated in time by 17.8 s. Assume the waves have traveled o

Georgia [21]

Answer:

D = 230.2 Km

Explanation:

let distance between seismograph and focus of quake is D

From time distance formula we can calculate the time taken by the S wave

$T_1 =\frac{D}{4.5}$

From time distance formula we can calculate the time taken by the P wave

$T_2 =\frac{D}{6.90}$

It is given in equation both waves are seperated from each other by 17.8 sec

so we have

$T_1 - T_2 = 17.8$ sec

Putting both time value to get distance value

$\frac{D}{4.5} - \frac{D}{6.90} = 17.8$

D = 230.2 Km

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3 years ago