You hear the engine roaring on a race car at the starting line. predict the changes in sound as the race starts and approaches the camera a. the sound of the engine will get louder and pitch lower b. the sound of the engine will get louder and pitch higher c. the sound is determined by the car and it will not change in anyway d. the sound of an engine will get louder but the pitch will not change

What occurs during a combustion reaction

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

If element x has 99 protons how many electrons does it have