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Volgvan
3 years ago
5

a train traveling at 72 km/h crosses a platform in 30 seconds what is the length of the platform in meters

Physics
1 answer:
Nookie1986 [14]3 years ago
3 0

Answer:????

Explanation:

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Answer:

Heat energy does not cool. Objects cool. Energy is not an object. Now, what happens when an object cools is that it gives off some of its thermal energy by one or more mechanisms: radiation, conduction, or convection. In radiation the energy escaped the object as electromagnetic waves - you see the red hot poker slowly dim as it cools, in conduction the energy is transferred Mechanically by the atoms of the hot object being in physical contact with those of the cool object and in convection the hot material moves to a cooler region where it gives up its heat energy by either radiation or conduction.

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3 years ago
What does hypothesis mean
k0ka [10]
Hypothesis means <span>a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation</span>
7 0
3 years ago
Read 2 more answers
Using an unmanned rocket to visit the space station requires 85.2 trillion BTU of energy. The best fuel for the mission will hav
Illusion [34]
We shall convert all of the densities to lbs/gal, so the product of
BTU/lbs and lbs/gal gives us the basis of comparison, which was "ratio of energy to volume".
grams / ml x 1 lbs/454 grams → 1 lbs/ 454 ml
1 lbs/454 ml x 3785.41 ml/gal → 3785.41 lbs/454gal
Conversion of g/ml = 8.34 lbs/gal
Looking at each fuel:

Kerosene:
18,500 x (8.34 x 0.82) = 126,517 BTU/gal

Gasoline:
20,900 x (8.34 x 0.737) = 128,463 BTU/gal

Ethanol:
11,500 x (8.34 x 0.789) = 75,673 BTU/gal

Hydrogen:
61,000 x (8.34 x 0.071) = 36,120 BTU/gal

The best fuel in terms of energy to volume ratio is Gasoline.
Gallons required:
BTU needed / BTU per gallon
= 85.2 x 10⁹ / 128,463
= 6.6 x 10⁵ gallons
5 0
3 years ago
Calculate the force of gravity on a 1–kilogram box located at a point 1.3 × 107 meters from the center of Earth if the force on
Sati [7]

Since you already gave us the weight of the 2.5-kg box,
we don't even need to know what the distance is, just
as long as it doesn't change.

Look at the formula for the gravitational force:

                           F = G  m₁ m₂ / R² .

If 'G', 'm₁' (mass of the Earth), and 'R' (distance from the Earth's center)
don't change, then the Force is proportional to  m₂ ... mass of the box,
and you can write a simple proportion:

                       (6.1 N) / (2.5 kg)  =  (F) / (1 kg)

Cross-multiply:  (6.1 N) (1 kg)  =  (F) (2.5 kg)

Divide each side by (2.5 kg):  F = (6.1N) x (1 kg) / (2.5 kg)  =  2.44 N .

5 0
4 years ago
Suppose you were asked to find the torque about point p due to the normal force n in terms of given quantities. which method of
igomit [66]

Answer:

T=Lnsin\alpha

Please check the attached

Explanation:

The torque can simply be calculated by multiplying the length of the rod by the perpendicular force n as shown in the attached figure.

Note that sin90=1

T=Lsin\alpha(nsin90)

T=Lsin\alphaxn

T=Lnsin\alpha

7 0
3 years ago
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