6.4.2 pratice

[ashtonly...@gmail.com]

1. One of the Mars Rover vehicles, Sojourner, collected red Martian dust on its wheels as it rolled along. There is very little water on Mars, so it's not mud; it's actually dust. Explain, in detail, why the dust clings to the wheels. Be sure to describe forces by name and mention charging by induction, conducting, or rubbing, if it is appropriate. Also explain what atoms on Mars must be composed of. (4 points)


like any other tire the tires on the martian vehicles have treads that invariably get dust and dirt in them. just like tires here on earth.




2. On Earth, electrical systems are usually "grounded," giving excess electrons a place to go. Household wiring has a "ground," literally a big metal stake pounded several yards into the ground. The stake is driven deep into Earth because, in most locations, soil is damp once you get several feet underground. Explain why damp soil helps the excess electrons move. (4 points)


Movement is something that is unneccessary but for some reason particles must move in order to express the energy that they hold.




3. Keep in mind that Mars is dry (so is the moon). Why do you think scientists are concerned that static electricity will be a much bigger problem for astronauts than it is for people here on Earth? (4 points)



When its dry outside we have more issues with static and being shocked than when it is wet outside. so if it is more dry on the moon and on mars than there will most likely be more static electricity



4. In the future, as astronauts walk across the Martian surface, they will acquire a static charge.

A. What will this create around them? (2 points)


energy,




B. If they accumulate a lot of charge, what might happen to sensitive electronics (in air locks, perhaps) as the astronaut approaches? (2 points)


They might have issues with them. or it might malfunction.





Current and Circuits:


5. Fuel, like diesel and propane, is too heavy for the Mars mission to carry much, if any, of it. So power is likely to be provided by a solar array instead of a generator. The energy collected from the solar arrays will be stored in large battery banks. Most of the circuits will have a load of about 12 Ω. If 4 A is needed to run the equipment, what voltage does the battery bank need to be? (4 points)


6




6. Design these circuits for use at the Mars station. Show sketches of the circuit. Then complete the math. (12 points)

A. A 12-V battery, running a motor. There's also a switch in the circuit so the motor can be turned on and off. Show this, too. If the motor has a resistance of 12 Ω, how much current goes through the motor? (4 points)



















B. One 24-V battery, charging up the Mars Rover. If the Rover has 120 ohms of resistance, how much current flows through it? (4 points)



















C. Four 12-V batteries, combined to produce a total of 48 volts of potential, running the heating system. (On a warm day, it might reach 60°F on Mars!) This circuit needs a circuit breaker, represented as a resistor. So put one in.
What is the voltage difference across the heater? If the heater has a 12 Ω resistance, how much current goes through it? (4 points)



















Magnetism


7. The floors of the future Mars Station will be metal-stainless steel, in fact. The gravity on Mars is about one-third of that on Earth, so when the astronauts walk they will bounce along.

A. To keep them from bobbing so much, what can they do to the bottoms of their boots? (2 points)







B. One of the future astronauts must extend a probe outside the station to monitor the atmosphere every hour. But she gets tired of manually pushing out the probe extension every hour. She has access to batteries, some wire, some iron, a timed switch, and some permanent magnets. What can she make so that she doesn't have to operate the probe by hand every hour? What purpose does the timed switch serve? (6 points)







C. As the teams start exploring the surface of Mars in the future, they will notice that they cannot use compasses for navigation. What is necessary for a compass to work as a navigation tool? Since compasses do not work on Mars, what can you conclude is true of Mars? (6 points)







8. During severe dust storms, when the dust swirls like a tornado, the Mars station will not be able to send or receive communication signals. All they will hear is static. Considering that wireless communications are electromagnetic in nature, why do you think this would occur? (4 points)