Have you ever heard a siren on a moving ambulance, fire truck, or police car? If so, what happens to the sound as the vehicle passes by?

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

Apulley system is used to lift a 2,000 newton engine up a distance of 3 meters. the operator must apply a force of 250 newtons to the chain of the pulley system to lift the motor. to lift the engine 3 meters, the operator must pull a total of 30 meters of chain through the pulley system. what is the value of di?

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?