Arock is dropped from a cliff.

what will eventually happen to the rock's motion?
a. gravity will cause the rock to slow down before it reaches earth.
b. air resistance will cause the rock to accelerate as it falls.
c. the rock will continue falling until earth exerts a contact force on the rock.
d. friction will cause the rock to continue in its state of motion.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Aweight lifter raises a 1600 n barbell to a height of 2.0 meters. how much work was done? w = fd question 6 options: 3000 joules 30 joules 320 joules 3200 joules

This is the substance(s) formed in a chemical reaction.