Amotorcyclist is traveling north on a road at a speed of 25.0 m/s. a police car, traveling south at a speed of 40.0 m/s, approaches with its siren producing sound at a freqency of 2600 hz. (enter your answers in hz. assume that the speed of sound in air is 313 m/s.) (a) what frequency does the motorcyclist observe as the police car approaches? (enter your answer to the nearest integer.) hz (b) what frequency does the motorcyclist detect after the police car passes her? hz(c) repeal parts (a) and (b) for the case when the police car is traveling northbound while police car overtakes hz after police car passes hz ?

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)