Pl HELLPPP ILL MARK BRAINLIES PROMISE
If the total mass of the products of a reaction is less than the mass of the reactants, what must be true?
A nuclear reaction has taken place.
A chemical reaction has taken place.
Nuclear fusion has occurred.
Nuclear fission has occurred.

Plss anybody know how to do this? ? i need the answers from a through d

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.)

Idon’t quite understand this problem