In physical science lab, ben and jerry added small pieces of magnesium to hydrochloric acid. they noticed that bubbles formed, the test tube got hot, and the magnesium disappeared. what is a sign that a chemical reaction has taken place in this experiment?

Anne applies a force on a toy car and makes it move forward. what can be said about the forces acting on the toy car at the moment anne applies the force?

Explain vector addition, triangle method and parallelogram method

An engineer designs a roller coaster so that a car travels horizontally for 152 ft, then climbs 137 ft at an angle of 34.0° above the horizontal. it then moves 137 ft at an angle of 48.0° below the horizontal. if we take the initial horizontal motion of the car to be along the +x-axis, what is the car's displacement? (give the magnitude of your answer, in ft, to at least four significant figures and give the direction of your answer in degrees counterclockwise from the +x-axis.)