A book rests on the shelf of a bookcase. The reaction force to the force of gravity acting on the book is 1. The force of the shelf holding the book up. 2. The force exerted by the book on the earth. 3. The weight of the book. 4. The frictional force between book and shelf. 5. None of these.

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.)

Which changes of state do the labels represent? a: b: c:

A26 cm object is 18 cm in front of a plane mirror. a ray of light strikes the object and is reflected off the mirror at a 42-degree angle. what is the angle of reflection? degrees what type of image is formed? what is the size of the image? cm