You pull a 20 kg box with a 25° angle up 35° ramp (with a coefficient of kinetic friction of 0.45)from its base for five seconds at an acceleration of 5 m/s. What's the Applied force needed to pull the box up the ramp?

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?