Explain why the top of the loop cannot be the same height as (or higher than) the top of the first hill. Assume the roller coast
er and its surroundings are close to a closed system. Use what you know about energy transformations and the effects of friction within a closed system to write your answer.
Passage
Examine this diagram of a roller-coaster track. The very top of the first hill (point B) is higher than the very top of the loop (point D). After the cars reach point B, this roller coaster needs no additional energy to complete its trip.
Passage
Examine this diagram of a roller-coaster track. The very top of the first hill (point B) is higher than the very top of the loop (point D). After the cars reach point B, this roller coaster needs no additional energy to complete its trip.
2 answers:
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Answer:
The correct answer is
Explanation:
The formula for the electron drift speed is given as follows,
where n is the number of of electrons per unit m³, q is the charge on an electron and A is the cross-sectional area of the copper wire and I is the current. We see that we already have A , q and I. The only thing left to calculate is the electron density n that is the number of electrons per unit volume.
Using the information provided in the question we can see that the number of moles of copper atoms in a cm³ of volume of the conductor is . Converting this number to m³ using very elementary unit conversion we get
. If we multiply this number by the Avagardo number which is the number of atoms per mol of any gas , we get the number of atoms per m³ which in this case is equal to the number of electron per m³ because one electron per atom of copper contribute to the current. So we get,
if we convert the area from mm³ to m³ we get .So now that we have n, we plug in all the values of A ,I ,q and n into the main equation to obtain,
which is our final answer.
2.71 m/s fast Hans is moving after the collision.
<u>Explanation</u>:
Given that,
Mass of Jeremy is 120 kg ()
Speed of Jeremy is 3 m/s ()
Speed of Jeremy after collision is () -2.5 m/s
Mass of Hans is 140 kg ()
Speed of Hans is -2 m/s ()
Speed of Hans after collision is ()
Linear momentum is defined as “mass time’s speed of the vehicle”. Linear momentum before the collision of Jeremy and Hans is
=
Substitute the given values,
= 120 × 3 + 140 × (-2)
= 360 + (-280)
= 80 kg m/s
Linear momentum after the collision of Jeremy and Hans is
=
= 120 × (-2.5) + 140 ×
= -300 + 140 ×
We know that conservation of liner momentum,
Linear momentum before the collision = Linear momentum after the collision
80 = -300 + 140 ×
80 + 300 = 140 ×
380 = 140 ×
380/140=
= 2.71 m/s
2.71 m/s fast Hans is moving after the collision.