A)some comets are in highly elongated orbits that come very close to the sun at perihelion. the distance from one such comet to the center of the sun is 6.00×10^9m at perihelion and 3.00×10^12m at aphelion. for this comet's orbit, find the semi-major axis. b)in 2017 astronomers discovered a planet orbiting the star hats-43. the orbit of the planet around hats-43 has semi-major axis 7.41×109m, eccentricity 0.173, and period 4.39 days. find the distance between hats-43 and the planet at its closest approach. express your answer with the appropriate units

1. a camcorder has a power rating of 19 watts. if the output voltage from its battery is 7 volts, what current does it use?answer units 2. a 1.5m wire carries a 6 a current when a potential difference of 57 v is applied. what is the resistance of the wire? yourunits 3. a clothes dryer uses about 2 amps of current from a 240 volt line. how much power does it use? yourunits 4.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

What is the ultimate purpose of the nuclear reaction in a nuclear power plant? -the reaction is used to create a magnetic field. -the reaction is used to create temperatures high enough to generate steam. -the reaction is used to create a high pressure system used to spin the turbine of the generator. -the reaction is used to prevent chain reactions. in a safety seminar at a nuclear power plant, a technician describes the procedure used if temperatures in the reactor become too high. what procedures should the technician describe? select all that apply. -more coolant will be pumped into the reactor. -the control rods will be taken out of the reactor. -the fuels rods will be lowered into the reactor. -the control rods will be lowered into the reactor. during a lab experiment demonstrating the relationship between pressure and water, mr. demming puts a beaker of water into a vacuum chamber. once the chamber is sealed, mr. demming turns the vacuum on. as the pump starts to take air out of the chamber, the air pressure inside drops relative to the pressure outside the chamber. after a few minutes, there is next to no air pressure in the chamber. what do you expect to observe in the experiment? -the beaker of water will crack. -the boiling point of the water will decrease and begin to boil at room temperature. -the boiling point of the water will increase, and will only boil at temperatures higher than 212 degrees f. -the liquid water will expand and spill out of the beaker since the air pressure no longer compresses the water molecules.