A powder and a liquid with a total mass of 20 grams are combined in an open beaker. A reaction occurs, as indicated by the production of gas bubbles. The final mass of the solution is less than 20 grams. What best explains the difference in mass?

Sort the images based on whether there's a force of attraction or repulsion between the magnets shown. attraction repulsion

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.

If state law mandates that elevators cannot accelerate more than 2.40 m/s2 or travel faster than 14.8 m/s , what is the minimum time in which an elevator can travel the 373 m from the ground floor to the observatory floor? ?