(UEFS) Considerando um corpo lançado horizontalmente nas proximidades da superfície terrestre, desprezando a resistência do ar e sendo g a aceleração da gravidade, é correto afirmar:

 Considere os exemplos de características anatômicas e fisiológicas de três seres vivos.

- O chimpanzé (Pan troglodytes) possui visão binocular e o primeiro dedo oponível nas mãos. A visão binocular permite que o cérebro distinga as diferentes distâncias entre os objetos observados e o observador e a presença do primeiro dedo oponível nas mãos permite o movimento de pinça, facilitando agarrar objetos.

- O inseto maria-fedida (Nezara viridula) libera um odor, produzido por glândulas toda vez que se sente ameaçado. Além dessa defesa, ele pode apresentar algumas colorações, como verde ou marrom, o que auxilia na proteção contra predadores.

- A planta urtiga (Urera baccifera) apresenta tricomas urticantes na superfície de suas folhas. Eles secretam substâncias ácidas, causando vermelhidão, coceira e ardência na pele de uma pessoa que as toca.

Esses três seres vivos apresentam

(ENEM SIMULADO-2009) O tráfico de escravos em direção à Bahia pode ser dividido em quatro períodos:

1^o– O ciclo da Guiné durante a segunda metade do século XVI;

2^o– O ciclo de Angola e do Congo no século XVII;

3^o– O ciclo da Costa da Mina durante os três primeiros quartos do século XVIII;

4^o– O ciclo da Baía de Benin entre 1770 e 1850, estando incluído aí o período do tráfico clandestino.

A chegada dos daomeanos (jejes) ocorreu nos dois últimos períodos. A dos nagô-iorubás corresponde, sobretudo, ao último. A forte predominância dos iorubás na Bahia, de seus usos e costumes, seria explicável pela vinda maciça desse povo no último dos ciclos.

VERGER, Pierre. Fluxo e refluxo do tráfico de escravos entre o golfo do Benin e a Bahia de Todos os Santos: dos séculos XVII a XIX.

Tradução de Tasso Gadzanis. São Paulo: Corrupio, 1987. p. 9. (com adaptações)

Os diferentes ciclos do tráfico de escravos da costa africana para a Bahia, no Brasil, indicam que:

(PUC-RIO) Driverless automobiles - The car that parks itself

CARS that need no driver are just around the corner according to researchers who have been testing vehicles bristling with aerials and cameras on public roads in America. However, researchers do not make cars, so it will be up to firms that do to bring the technology to market. And carmakers are a conservative bunch. Still, slowly and steadily the autonomous car will arrive, with the help of an increasing number of automated driving aids. A Swedish carmaker has recently demonstrated one such feature: a car that really does park itself.

Some cars already have systems that assist with parking, but these are not completely autonomous. They can identify an empty parallel-parking space and steer into it while the driver uses the brake. The Swedish system, however, lets the driver get out and use a smartphone application to instruct the vehicle to park. The car then ¹trundles off, manoeuvres into a parking place and sends a message to the driver to inform him where it is. The driver can collect the car in person or use his phone to call it back to where he dropped it off. Autonomous parking could thus be provided at places like shopping centers and airports, which are controlled areas in which automated vehicles can be managed more easily than on open highways.  In the past, designs for doing this have relied on car parks being fitted with buried guide wires that a vehicle can follow to an empty bay. That, though, creates ²a chicken-and-egg problem: car-park operators will not invest in such infrastructure until there is a sufficient number of suitably equipped cars on the road. Drivers, conversely, will not want to buy self-parking cars if there is nowhere to use them.

This means, as a safety engineer working on the project observes, that for autonomous parking to work most of the technology will have to be in the car itself. The test car, which looks like a normal car, therefore uses on-board GPS mapping, cameras with image-recognition software, and radar sensors to find its own way around a car park and avoid pedestrians and non-autonomous vehicles. The same engineer says the system is five to ten years from commercial deployment. If it proves a success then infrastructure might adapt to it, for instance by packing cars into tighter spaces. If there is no one in them there is no need to make room for their doors to open.

Driverless cars would also need to communicate with one another, to enhance safety. That, too, is coming. ³A number of carmakers are developing wireless networking systems through which vehicles can exchange data, such as their speed, their steering angle and even their weight, to forewarn anti-collision systems and safety devices if an accident looks likely.

In the USA, for example, a carmaker recently tested a brake light that can provide an early warning to other motorists. If the brakes are applied hard in an emergency, a signal is broadcast. This illuminates a warning light in the dashboard of suitably equipped following vehicles, even if they are out of sight around a bend or not immediately behind the vehicle doing the braking.

The American company has been testing this system as part of a collaborative research project with several European carmakers. ⁴They have put a fleet of 150 experimental vehicles on the roads. When they tested a group of these, the Americans found the technology let drivers brake much earlier, helping avoid collisions. A driverless car would be able to react even faster.

Another member of the research group has been testing driverless cars on roads around Munich— including belting down some of Germany’s high-speed autobahns. ⁵The ordinary-looking models use a variety of self-contained guidance systems. These include cameras mounted on the upper windscreen, which can identify road markings, signs and various obstacles likely to be encountered on roads.

The German cars also use a radar, to gauge how far the vehicle is from other cars and potential obstacles, and a lidar, which works like a radar but at optical frequencies. The lidar employs laser beams to scan the road ahead and builds up from the reflections a three-dimensional image of what this looks like. The image is processed by a computer in the vehicle, which also collects and compares data from a high-accuracy GPS unit. A series of ultrasonic sonars similar to those used in vehicles to provide parking assistance are placed around the car to add to the virtual picture. And just to make sure, a set of accelerometers provide an inertial navigation system that double-checks the vehicle’s position on the road.

⁶Although these cars can be switched to an autonomous driving mode, they are still required to have someone in the driving seat who can take over in the event of any difficulty. Some cars can steer themselves, slow down, brake and accelerate, even changing lanes to overtake slower vehicles.From the print edition: Science and Technology Jun 29^th 2013 

The author uses the phrasal verb “trundles off” (ref. 1) that could be replaced by:

(ENEM 2016 3ª APLICAÇÃO)  Um pesquisador preparou um fragmento do caule de uma flor de margarida para que pudesse ser observado em microscopia óptica. Também preparou um fragmento de pele de rato com a mesma finalidade. Infelizmente, após algum descuido, as amostras foram misturadas. Que estruturas celulares permitiriam a separação das amostras, se reconhecidas?