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 coaster 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.

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

What property of an object determines its inertia?

Acold front traveling southeast collided with a warm front traveling northwest the following map shows the weather on monday the day the two fronts collided which of these describes the weather forecast for mississippi on tuesday and wednesday