Suppose that the most massive car ever built is moving down a 10.00 slope when the driver applies the brakes. The net force acting on the car as it stops is -2.00X104 N. If the coefficient of kinetic friction between the car’s tires and pavement is 0.797, find the car’s mass. What is the normal force that the pavement exerts on the car?

Atrain is traveling at 30.0 m/s relative to the ground in still air. the frequency of the note emitted by the train whistle is 262 hz. the speed of sound in air should be taken as 344 m/s. what frequency (f approach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and approaching it? what frequency (f recede) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and receding from it?