Describe how the doppler effect explains why an approaching fire engine's siren has a high pitch?

Atriangle with equal sides of length 10 cm has -2.5-nc charged objects at each corner. part a determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. horizontally rightward vertically downward vertically upward horizontally leftward

Wo dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. the block in (figure 1) has a mass m=10kg and is being pulled by a force f on a table with coefficient of static friction îľs=0.3. four forces act on it: the applied force f (directed î¸=30â above the horizontal). the force of gravity fg=mg (directly down, where g=9.8m/s2). the normal force n (directly up). the force of static friction fs (directly left, opposing any potential motion). if we want to find the size of the force necessary to just barely overcome static friction (in which case fs=îľsn), we use the condition that the sum of the forces in both directions must be 0. using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: fcosî¸â’îľsn=0 fsinî¸+nâ’mg=0 in order to find the magnitude of force f, we have to solve a system of two equations with both f and the normal force n unknown. use the methods we have learned to find an expression for f in terms of m, g, î¸, and îľs (no n).

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.