i got (D, B)
1.) Which is not a medium through which a mechanical wave could travel?
A.) liquid water
B.) oxygen gas
C.) jump rope
D.) empty space

2.) Waves from the sun .
A.) are called mechanical waves
B.) transfer energy from the sun to Earth
C.) cause the Earth to vibrate
D.) require a medium through which to travel

An engineer designs a roller coaster so that a car travels horizontally for 162 ft, then climbs 127 ft at an angle of 31.0° above the horizontal. it then moves 127 ft at an angle of 46.0° 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.)

Awoman stands a distance d from a loud motor that emits sound uniformly in all directions. the sound intensity at her position is an uncomfortable 2.0×10-3 w/m2. at a distance 2.6 times as far from the motor, what are (a) the sound intensity and (b) the sound intensity level relative to the threshold of hearing?

An object has a weight of 500 on earth what is the mass of this object